I like DJ Fresh but his beats aren't big or nothing, they're right for the rappers he works with.
After that, I haven't been paying much attention to beats because I just assume shit is made by someone's homie in some apartment complex somewhere.
All those groups that be fucking with DJ L1L D3BB13 (Alexander Spit, Bago, CBG, Kreayshawn) all have tight beats. Hit her up, see whose she's fucking with.