Love steam, and try to buy all my games through there, but my one experience i had with origin support was good.
I bought BF3 from origin, and after i couldnt solve the problems i was having they gave me a refund. The CS rep did a good job, and i couldnt have asked for more from them.
On the other hand, im not wild about installing more software. I love steam, and wish i could just load up whatever games i bought through origin from steam. The fact that you HAVE to use origin kinda sucks. The web interface with BF3 was a little weird too.
I dont think its enough to make me not buy a game that i wanted really bad though. I mean, im somewhat excited for diablo 3, and if i had to install origin to play it i would have no problem. Might be a little upset but oh well. That story about the installs was crap though, id be pissed too.