So far its been an enjoyable experience for me.
Up to Nightmare Act 3 with my Monk.
When they said, "You will die." they definitely were not kidding!
As for gear and all that I haven't bothered at all with the AH.
Doing it the old fashion way find it, ID it, Use it or sell it.
The AH seems confusing to me and there is a lot going on there.
Anything I think my friends might be able to use I hold onto in case they need it.
I can't even imagine what Inferno will be like!