Totally in my opinion, the top 4 for me
Alliance (Recently whooped all of Asia at the G1, Loda shacking up with Kelly Milkies e-drama)
LGD.CN (best at what they do - ricer style dota)
Na'Vi (Still batpoo crazy lineups with fearless ganking)
Mous (Consistent good play, I highly rate synderens picking)
Just outside of these I'd pick Orange and TongFu.
You guys might be interested in the tier list for July to get some idea of what to expect:
https://docs.google.com/document/d/1xVhGGEUqE90Ogqdjw_6NzzQ2FsQa4WMywz5alUlrylo/pub
To explain some of the tier for the new guys / returners
Batrider is just a complete sod as he makes every fight 4v5, both east and west like him.
Alchemist is 100% ban in east because they do defensive rice dota - they lose the lanes, hold out in the midgame, rule the late. Countered by push strats / gank lineups and forcing alc to go acid/stun early game.
wisp is 100% ban west because his early/mid is crazy, western teams like to have games done by 35 mins of preference. Commonly countered by quick pushing / defensive trilaning but even you can expect hassle.
Other risers:
Razor is hero of the month as he counters lone druid with tether, a popular pick.
Weaver is a PITA to deal with, does well in lane, requires a partial stunlock team to counter.
Naga is back as a support, net goes through BKB, song is extremely useful to isolate BKBers or setup/run away from a fight.
OD counters common mid picks, crazy damage ult.
Nyx: nyx nyx nyx nyx nyx nyx nyyyyyyyx.