Both have about the best customer service you could ever expect, but like I said in my previous post- RIA is the only one that I have never heard a single complaint about. go and check out the RIA forum on m1911.org- RIA customer service reps frequent it and stay on top of everything.
Honestly, RIA has something to prove right now and they know it- they're breaking the mold of what it means to be a "cheap" 1911. While they might skimp on finish to keep the costs down, they are going to make sure their guns function as well as possible and stay right on top of any problems. They are building a reputation and are doing a great job at it.
There isn't anything inherently wrong with the ILS- it's just some people don't like the lawyers meddling with their guns. It's like the people that won't buy a new S&W because of teh hammer lock.
As for hammer bite, I'm pretty sure ALL beavertail safeties require reshaping the rear of the frame and opening up the safety slot since they are wider as well.
I'd recommend finding someone with a mil-spec 1911 that will let you shoot it, see if hammer bite is an issue for you at all. Honestly, i think it's blown a bit out of proportions. if the gun has an A1 hammer and not a WWI hammer, i don't think it would actually be possible for the hammer to contact your hand.
Find out what you like and want, and get either the RIA or SA that meets your needs- you really can't go wrong either way.