Size matters

[Emperor Demonking]

Are Small & medium equal? If not which is better.
What about small and dwarf medium?

Is tiny better or worse than medium?

[Xefas]

Depends what you're doing.

A stealth class gains good benefits from being small size. +1 AC helps their lack of heavy armor, the +4 to hide is a great bonus, and all the penalties aren't too big an issue for you (I rarely see rogues or beguilers going for the big grapple).

Arcane Casters, too, gain a good benefit. +1 to AC to help their lack of heavy armor, and +1 to hit for ray spells. They, too, aren't really inconvenienced by the penalties, even less so than the stealth classes since they're not likely to be using weapons as their main source of contribution.

Above all else, though, if your DM isn't using a tactical battle grid, he's likely just buffed all small races in the game. The worst part about the small races, in my opinion, is reduced speed, and when your DM is using abstracted distance, he isn't likely to take that in to account (plus he'll fear sounding like a heel saying "Ohhhh, sorry, you can't make it to him by 5ft. Minotaur hits you for 34 damage", which is easily justified when you're on a grid).

Tiny races are almost absurd for a PC race. Playing a melee class with one is all but out of the question. Ranged has the problem of you most likely having a low speed, so enemies can close with you very quickly. With stealth classes, you run the risk of logic being inserted into the game ("Hey, how does a Sneak Attack from a Tiny Dagger that can't reach past a guy's ankle do the same +7d6 damage as a Medium Dagger to the gut?" or "How come every "dose" of poison is enough to coat a single weapon regardless of size whether sized for Tiny or Colossal? And how come a tiny pinprick of poison does the same ability damage with the same DC as a kidney full of it from a poisoned greatsword?").

[Armads]

Small and Medium being better or worse depends on what you're doing. Small's better for casters/stealth people, while medium's better for frontliners.

Tiny's generally much worse than medium for frontliners, and has the drawback that Wind Wall stops you, but it's great for casters, although there are some neat tiny frontliner builds (like here). The main problems are Wind Walls and Reach.

[Cuddly]

Being tiny means you have to move into the other dude's square, doesn't it?

[KillianHawkeye]

Yes, and you provoke an attack of opportunity for doing so.

[Ne0]

Except if you go into the whole underfoot combat line of feats. I always liked those. Good for a melee class, I'd say.

[leperkhaun]

basically the only problem iv ever had with small races was their movement speed.

[Person_Man]

In general, I've found that unless your build depend specifically on being very big (King of Smack et al) Small is better. Bonus to AC, to-hit, and Skills - plus you can ride medium mounts pretty much anywhere, which is helpful for almost any build. Strongheart Halfling is one of my favorite races.

[Treguard]

Whilst I love LogicNinja's killer gnome build (link provided above), correct me if I'm wrong but doesn't uncanny dodge shutdown the build's damage output? You can't flank so you're constantly relying on making them flatfooted for schweet SA.. See what i mean? Telling Blow could remedy this.

That's the only reservation I have over this fun lil' build.

[CactusAir]

Whilst I love LogicNinja's killer gnome build (link provided above), correct me if I'm wrong but doesn't uncanny dodge shutdown the build's damage output? You can't flank so you're constantly relying on making them flatfooted for schweet SA.. See what i mean? Telling Blow could remedy this.

That's the only reservation I have over this fun lil' build.

You rely on denying dex to AC. There are other wasy fo doing that then making someone flatfooted. And a flatfooted character is still flatfooted (and vulnerable to Iaijustu Damage) even if he retains Dex to AC.

[Treguard]

Good point. I forgot about stunning, blinding, invisibility etc.