Deciding on a system

[Telonius]

Hello everyone! I'm in the planning stages of a new campaign. I've got most of the plot elements worked out, but am having some difficulty deciding on a system.

The general idea is that the players are ordinary citizens of a fantasy metropolis - think Ankh-Morpork of Discworld. The players are recruited by the local ruler to become a team of masked vigilantes (technically extra-legal, since the mayor can't be seen as directly supporting them) to help with the city's growing crime problem. To achieve this, they'll each receive a magical item called a Mask of the Heroes, that changes the appearance and outfit into an idealized version of themselves. (Depending on what ruleset I end up using, they'll get their class levels when it's on, etc).

I'm planning for the adventures to be mostly investigation, with much less emphasis on combat and more on social interactions. There will definitely be fighting of goons and supervillains, but this will be sprinkled in as opposed to being the main focus.

I'd originally thought to make this a D&D 3.5 / E6 campaign, since 3.5 is what I know best. But D&D is (famously) combat-focused, and I'm not sure how well it would actually mesh with what I'm trying to do. Recently I've been looking at some other options. In particular I'm looking at Mutants and Masterminds, and Masks: A New Generation (from Magpie games). I do have some concerns about both of them. Mutants and Masterminds seems like it would be much, much more one-on-one work for me as the DM to rate and balance every little power that the players could come up with. And while I really like the concept of Masks, I'm a bit concerned that it's going to be too teen-angsty for my group (mostly in their 30s and 40s). Note that I haven't actually seen the full ruleset yet; just going from the free .pdfs and reviews I've seen online. I'm more than happy to re-fluff or rename some of the stats (if it turns out the rules are amenable to that) to make it less of a "been there done that don't want to relive it" thing for the group.

So, from the little bit I have outlined, what would you recommend? Go with what I know, Mutants, Masks, something else?

[kyoryu]

Gumshoe seems reasonable, as its focused on investigations.

Fate would certainly work.

I haven't mucked with it much, but I think Cortex+ would be pretty good.

[Knaight]

I'd seriously consider Blades in the Dark for this. Urban crime gangs are a bit of a focus, as are long projects, with combat largely deemphasized but still there.

[Rynjin]

Mutants and Masterminds 3e would be pretty easy to GM for, actually. Most effects of powers are clearly labeled in the book and then refluffed to fit a character. Just set reasonable guidelines at start for what kind of power level and how much munchkining is acceptable.

I also like to recommend Savage Worlds to people. it's a great system for a low power campaign where heroes are hard to kill but not wholly superhuman. The system basically works on action movie logic, but has a good skill system for less combat-y games too.

[Beleriphon]

Mutants and Masterminds 3e would be pretty easy to GM for, actually. Most effects of powers are clearly labeled in the book and then refluffed to fit a character. Just set reasonable guidelines at start for what kind of power level and how much munchkining is acceptable.

As a bonus M&M 3E has d20herosrd.com which is free, and more or less a full ruleset, at least in so far as one needs to actually figure out what you want to do with the rules.

[Jay R]

Of the systems that can work at all, I recommend the one you are most familiar with.

Almost always, an adequate game system that the GM knows really well is superior to a game system that is theoretically best for the scenario that the GM is unfamiliar with.

[Telonius]

Thanks for the advice everyone!