What is the best firmware for jailbreaking nowadays? 11.6? stability, compatibility, game format support? im on 10.1
To be sure, 10.01 is a perfectly fine firmware version to play games on. It's the highest firmware that has access to all three modern kernel exploits (Lapse, Pooposploit, and Relapse). On paper, compatibility obviously isn't as good as 11.xx firmwares (fewer backports needed), but it's a relatively narrow selection of games. Most everything of note is getting backported to at least 9.xx.
With that said, if you are
just going to play games and want to run a newer firmware? 11.20.
11.20 is a very good firmware version for games because it's one of the highest firmware versions that supports fPKG games. And it (still) has multiple stable kernel exploits available, with both Poopsploit and Relapse.
11.40 and 11.60 are your other 11.xx options, but there aren't as many exploits available for those firmwares and game compatibility is going to be the same regardless.
I have to caution that firmware upgrades are a one-way process, though, so there's no going back. Will someone find a super awesome and highly reliable untethered jailbreak for lower firmwares (or better still, a full CFW)? Maybe. So the risk you take is that you are potentially locking yourself out of future developments. But it means you get to play (more) games now.