Blizzard > EA. Much more thorough in testing their games prior to release for bugs, balance, playability, etc.
Personally I'm waiting until prices drop a little, as I was in the beta but wasn't terribly impressed. My late middle school/early high school years were essentially burned on SC, and some of the changes from the original I can't say I enjoy. However, I do plan on enjoying the single player campaign, in a slightly less frantic environment than multiplayer. Maybe I was just younger and faster, but I simply couldn't enjoy the Beta due to the pace, which felt significantly faster than I remember.
My G/F got Sims3 right when it came out, and only within the last week was she able to actually play it, as it would lock up her computer on a regular basis. Last week they came out with a patch and all has been well ever since. So it's been... what... A year now? maybe longer?
Sims2 was the same way.. my ex-wife played it all the time but all kinds of quirky things happened until they finally patched it several months after its release. Her characters would have a baby, but the baby would disappear and since it was gone they couldn't feed it or bathe it and family services would eventually come take it away LOL.
I have to say though, Sims2 was pretty clever... my ex- was playing a husband and wife... and while the wife was at work the husband invited the neighbor lady over and they were getting it on. While this was happening, the wife's mother came by for a visit, saw the other woman and left. The husband left for work later on. The wife came home from work and her mom came over and visited. Then the mom left. Then the husband came home and the wife slapped him across the face!!! HAHA I was laughing my butt off!
Yes Blizzard does release patches, but these rarely have anything to do with reliability of the software.. it's usually little things like speed improvements, or balancing changes.. things like that.