Got my dps to 15k last night and so far I am enjoying my high DR/resists/HP build.
Once I have cleared the minions I can actually tank most rares in Act1 which yields actually far higher dps ( enemy isn't moving so hydra poison stacks up a lot and I can spam my attacks and not loose dps at all).

Haha, so damn true!

I haven't had any problems whatsoever. Runs at 70-90 fps with no slowdown even in massive carnage areas with other players. I'm in inferno now with my 60 Barb with 33k life unbuffed 10k dps unbuffed and occasionally crit for 32k buffed. I soloed Diablo in hell but am getting my ass kicked in inferno Act 1.

Nice Barb, but 4K Armor is nothing for Inferno. How much resistances do you have? You should aim for at least 8K armor and 500 resists all around to make it at least manageable (don't even try to tackle Act II without at least the 500 resists, or the dune flies will destroy you).

Also, you play in the america server correct? No wonder you're not having any problems, since it's only the EU and Asia servers that are having a shit ton of problems. Blizz are really droping the ball on those two and it's getting worse as the days go along. 

On 1st week launch, NA server was a gigantic piece of crap.

Every server was crap on 1st week, but they got their shit together and managed to stabilize the NA server. From what I read in the us.battle.net/diablo3 forums is that the few error occurancs center around Error 3007 (disconnect errors) and even then it's really a minority of cases. 

EU and Asia servers on the contrary have been in a constant myriad of errors. For the past 3 days it's been pretty much as bad (if not worse) than launch day, with Error 37, 73, 1, 300008, 315000, etc. constantly bombarding everyone on the servers and not just a fraction of the gamers. Error 1 was particularly bad, everyone got scared that their characters had been erased since after login in, the only thing you saw was a blank generic banner and an Unknown character tag with level 0.

After 1st week, NA server was just a piece of crap with all those errors that you mention, and a lot of server maintenance issues.   Right now the server is "stable", but still with problems.

Sometimes when trying to play with my brother, I "join" but the game stays in the screen after you log-in showing my character and the banner.   When that happens I need to quit the game and retry, hoping for it to not happen again.

There are times the lag is atrocious, and the game unplayable.

Wow - sorry to hear you guys having problems. I'm on american server and have never had lag and any of those errors after the first few days. I've logged well over 100 hrs into game so far.

Working my way through Inferno Act 2 solo and this is no piece of cake.
It actually wasn't so bad until I hit the Cave of Betrayer and then I was stucked there forever.
There's just no way i can beat a spider Broodling champion or rare in those tight corridors when even without the fast mod they already move faster than me...
I think I reloaded that dungeon like 15 times and ended up parking the bosses of the first level in a corner and skipping them...( and weirdly enough after that I moved to the Vault of the Assassin where I killed like a dozen champion and rare packs and skipped nothing)

I'm in the Archives now and I should get past it toonight..
The last part hasn't been good for my cash though, I was dying so much the gold I was making was just covering for repairs...
Thankfully I found a WD offhand early in Act 2 I was able to sell for 1 million so that allowed me to do a few upgrades...

I'm sitting at 20.4k dps, 32k hp, 6300 armor and 400 or so resists with buffs...
Nothing one shots me but it's still no piece of cake...

One change I'm going to have to make soon is probably get away from Diamond Skin and switch to teleport as there are way too many situations where the skin can't save me where a teleport actually would..

Now that I have spent more time in D3 with my wiz and my barb I really wish we had one more skill button. It would make the game better giving us more choices but still woudn't imbalance things too much...

I hope the expansion brings this. 1 more skill and 1 more passive would be perfect...

Cave of the Betrayer... I was lucky, only restarted it 7 times!

Act II gets incredibly hard about halfway through, the first half wasn't so bad. I can't imagine how I'm going to beat Belial on Inferno, he's probably the hardest Act boss of them all on this difficulty, no room to move and every attack one-shots you. I expect Azmodan to be ridiculous and simple as usual though, I only need to get there first to confirm...

Agree about the skill slots too, one more Passive would be great. As it is, you have to choose between DPS and living longer. Problem is; if you sacrifice DPS for longevity, you end up dying anyway since you need a lot longer to take down the mobs. Full DPS rush has worked for me so far on Act II and I still have pathetic armor and resists on my DH.