Monk and DH experiences:
Leveled monk first, it was hard but doable (getting gear from AH of course) until start of act3 inferno, then got totally stuck there as gear is just not enough to tank long enough. I thing basic problem with monks is they do too low damage, afaik they are by far lowest dps class.Even though barbarians dps number can be low too in charsheet, they got lot more burst? Wondering if should go just offensive and buy 2h high damage weapon and try to nuke mobs fast but no idea if its reasonable with monks. For non-monks reading this, monk can tank pretty much anything for like 10 sec chaining cooldowns even when undergeared.
Then leveled DH, at inferno levels much different compared to monk. Act1 was pretty faceroll thanks to ridiculous dps, but Act2 was total bitch, gotta love all those ground burrowing/invisible mobs one shotting you. Still doable with lots of dieing and faster than monk was, but there was less room for error as DH gets one shot by mobs so single mistake/not being awake and pressing smokescreen 0.2 second too late -> new corpse run. Dh kills blues/yellow much better than monk but monk is better against trash. End of act2 boss (was it Belial) was really hard for me as DH. Boss Phase 2 is really hard as i dont have enough dps to go over it fast, after 5 hours got first time to phase3 and one shot it. Onwards to Act3 and this is maybe easier than act2 for DH, also loot drop quality difference is huge. Act2 dropped pretty much nada, act3 I am getting decent loot LOT more. Probably finishing act3 today as it its not been really that hard except when playing tired and dieing 4 times in a row against same Soul Ripper. Because its so hard to remember that mob is still in same exact place where I died previous time...
Btw I love using Spike Trap with Scatter, invaluable against Soul Rippers and invisible or burrowing mobs. Also nice against reflecting mobs, drop traps, when mobs run over them pop Smokescreen to not get damage.