In many respects, the *quality* of Colt guns is fine. With the exception of a few plastic parts on the Colt (trap door, buffer) that should be aluminum, the average Colt and Bushmaster are about the same in quality.
The problem with the Colt is the non-standard pin sizes (fire control parts on post-bans, pivot pin, er screw, for pre-bans) which make it difficult to use with standard parts. Yes, replacement parts are available, but there is NO EXCUSE why Colt parts shouldn't be interchangable with any other AR. It was a political decision that is a slap in the face of civilians.
Also, there's the price issue. Colt's manufacturing price is lower than anyone elses, because they make more guns than anyone else, and their equipment has long been paid for. Yet, they are the highest priced guns from the factory. That would be justifiable if you couldn't get an equal or perhaps slightly better quality gun for less, but you can. The higher price is strictly paying for the name.
Personally, even if every part on a Colt gun was of standard size, I wouldn't pay a cent extra over the price of the same-configuration Bushmaster, which would be of equal quality. I don't pay for names when all else is equal, and I avoid buying things from gun companies that don't support civilian ownership 100%.
Could I trust my life to a Colt? Yes. Does it make sense to buy a Colt (other than for collector value, possibly) when Bushmasters exist for the same money, or more often, much less? No way.
-Troy