Personal preferance thing for sure.
But, I will tell you some things I learned along the way.
Grip safety
I'll never again buy a 1911 without a beavertail grip safety. The hammer bite I would get from the Mil-spec truly made the gun not fun to shoot. I bought the parts (grip safety, hammer and sear) to have a local 'smith install the new beavertail safety for me. Long story short, I spent more money in the long run by upgrading the safety than buying one factory installed. Plus, the pistol does not look as good as a factory one and it took a lot longer time than promised by the 'smith to do the work.
Trigger
I found I much prefer the length of pull offered by the longer triggers. Compare the short Mil-spec trigger to any Kimber or a SA Loaded and see what I mean.
Thumb Safety
I much prefer the longer thumb safety of the Kimber. The short safeties are harder for me to opperate quickly.
Sights
I found a NEED for night sights. Better to get them from the factory. You'll pay more in the long run to change them later.
Adjustable sights are for a target-only pistol. Fixed sights for me.
Extractor
Although I have had no problems with my one Kimber external extractor model, I much prefer the internal extractor. Kimber has gone back to this. I bet for a reason. Some people have had lots of problems.
Other
All that fancy checkering does nothing for me and costs a lot of extra cash. Glad I didn't get it.
I've had no problems with Wilson 47D mags. I like them best.
Hope this helps. You can try my pistols any time you want. My favorite 1911 is a Kimber Custom II with Night Sights. All the fancy high-end stuff does nothing for me.
Mark