Help me understand differences between pf and 5e

[Consensus]

My gaming group plays both pathfinder and 5e games. The pathfinder one has been going on for about half a year more or less, but I'd like to get a better understanding of the system. I already have a pretty general understanding but I'd like to be aware of things that would generally trip up someone who has a good mastery of 5e, but only half a year's experience in pf (and none in 3/3.5 for that matter.)

[JNAProductions]

Honestly, the biggest thing I can say is assume nothing.

Don't think that just because things share a name or seem similar that they work the same. Pretend you're a total novice, and learn from the ground up.

There are plenty of similarities between the systems, but there's enough differences that it's best to just go in fresh.

[TotallyNotEvil]

There's an actual skill system in place.

Also, potent and diverse magic items with a comprehensive crafting system.

Feats are nowhere as good/comprehensive as they are in 5E. PF is particularly guilty of this due to many feats from 3.5 being split up in two or three pieces, even if you gain one every odd level.

Attributes go higher than 20.

Your overal level matters far less than what you've chosen to fill them up with.

Casting mechanic isn't uniform, and you have some very interesting "pseudo-casters" like the Summoner.

Most of all, keep in mind classes are tools for you to build your character with, you won't need to define your entire progression on your very first level.

[NomGarret]

There’s a lot of bonuses of a lot of different types. This means many, but far from all things stack. If numbers seem too high to be true, make sure you aren’t doubling up on things which can’t.

[exelsisxax]

My gaming group plays both pathfinder and 5e games. The pathfinder one has been going on for about half a year more or less, but I'd like to get a better understanding of the system. I already have a pretty general understanding but I'd like to be aware of things that would generally trip up someone who has a good mastery of 5e, but only half a year's experience in pf (and none in 3/3.5 for that matter.)

They are totally different games and it would be wholly unreasonable to treat them as if they were mutually coherent. Do not treat ANYTHING as if it applies to both games. Nothing you know about 5e is at all relevant to playing PF, and vice versa.

tl:dr it's all different.

[GrayDeath]

TL;DR: Both use the same kind of dice and share a Name, the attributes have the same names, and many of the races are bearing the same names.

The rest is slightly to vastly different.

[NomGarret]

If you’re looking for a comprehensive idea of the differences as opposed to a list of which spells are weak in one edition or strong in the other, perhaps a comparison of their design goals (intended and otherwise) and the kinds of games they more naturally support?*

*Standard disclaimer that a good GM can overcome any rule shortcomings.

[Elder_Basilisk]

I'm not terribly experienced with 5e, but having started playing a bit, I'd say one important difference is where the multiclass traps are. In 5e, it's relatively easy to multiclass and maintain useful spellcasting ability since that stacks across multiple classes. However, martial ability is a much bigger challenge because the various attack and damage increasing abilities don't stack or scale. So, if you are a fighter 4/cleric 16, for example, you can cast 9th level spells but you still only have one attack.

In Pathfinder, on the other hand, all classes martial abilities stack and that fighter 4/cleric 16 has as many attacks as a fighter 20. On the other hand, spellcasting abilities do not stack, so the fighter 4/cleric 16 does not get to cast 9th level spells.

In both cases, multiclassing is full of traps and requires you to pay close attention to get it to work for you rather than sabotage you but the traps are different.

[Acanous]

Pathfinder works a lot more like 3.5, so many of the differences between 3.5 and 5e apply.
Pathfinder's archetypes are kind of a middle of the road between 3.5's "levels are a toolkit" and 5e's "Set it and forget it". If you're using 3.P you have a full customization kit before you, with more options- good and bad- than you'll be able to get through in any number of games. If you go 5e, your classes are basically set in stone. you can technically multiclass, but the requirement/reward on the chart basically guarantees you only get stuff you probably had anyway- or at least the option to get. With the addition that "You must meet the requisites for ALL of your classes prior to taking another class" you really can't use multiclassing to diversify. (Cleric/Paladin gets you nothing, Ranger/Druid gets you nothing, Bard, Rogue and Fighter are worthwhile options) and with multiclass spellcasting working how it does, there's almost never a time where it's good to try for theurging. Warlock being the exception that proves the rule.

Pathfinder does similar things- the Prestige classes that exist suck, there are "Mixed" base classes like the Bloodrager, Inquisitor, and others which already provide a 1-20 template for a lot of the ideas you might want to pursue. Multiclassing, while not pointless, detracts more and offers less than it did in 3.5. You can, however, make a good run of it. The best PF builds have a splash of multiclassing in them.

Skills. Skills are very different between the editions. in Pathfinder, Skills work nearly identically to skills in 3.5, except that your first level multiplier is replaced by a bonus to class skills, and non-class skill penalties have been entirely removed. It actually makes for easier times playing with non-class skills overall, though the intent was "set it and forget it". You still get some leeway to divest points across your levels to pick up new skills.
5e, you really set and forget your skills. Unless you are a rogue or a bard, you have nearly no control over your skills and how they increase over time. The downside is you have almost no flexibility. The upside is that all the target numbers are lower- and stay lower through the whole game, meaning someone with no skill bonus at all but a 20 in the relevant stat can still make the roll in most situations.

5e also puts a lot more emphasis on your character's natural stats, which Pathfinder was starting to do, but quite a bit moreso. Where Pathfinder killed a lot of stacking bonuses and made certain things harder by tinkering within the magic system, 5e flat out gutted the art of magic combos by making almost every spell that can be used in conjunction with another for greater effect into a concentration spell. So unless you have a party of casters, flying while invisible is next to impossible- or at least takes up one of your (Much more limited) magic item slots, or locks your race, etc. Combos can still be done, but you have to work harder for them and they lock build choices instead of just preparing them at the beginning of the day.

Pathfinder has a lot more magic items accessible to a character. You can have boots of flying and a headband of charisma and a belt of constitution and a ring of elemental summoning and gloves of the archmagi. In 5e, you have to carefully read the description of each item you wish to equip, as you can only have 3 bonded items. You can still end up with magic armour, magic weapons, and three cool magic items, but your build options are much more limited and swapping out is harder.

To sum it up, Pathfinder streamlined 3.5 some, and added some interesting things while taking away a few toys. 5e gave every character the sorcerer's problem- lots of stuff to select from, very few choices to keep, and those choices are locked for a good long while.
This actually does make encounter design easier on the DM, and does simplify the game while making the magic items feel more important. bonuses are also smaller.

Creating a 3.5 character could take literal days while you figured out a 1-20 build. Creating a Pathfinder character takes maybe an hour. Creating a 5e character can be done in 5-10 minutes.