Consider this...
Consider the following...but bottom line, go for a test drive.
1. Any gun is just a tool...so ask yourself what is the job? Get the right gun for the right job. Home? CCW? Competition? A new toy? Curiosity piece?
2. Purchase price range?
3. Amount of additional $$$ required to get it to meet your needs.
4. Reliability for years to come.
5. Materials / style / preference? Stainless? Steel? Aluminum? Plastic?
6. Local law constraints (e.g. CA DOJ "approved-only" handgun list).
7. Go for a test drive.
I own and have shot more types of .45's than I can count. My absolute favorites are Kimber Team Match II 1911 Stainless and the Sig P220 ST. Although I shoot HK's, Berettas, Glocks, Paras, Rugers, they each have their own drawbacks (reliability, overpriced, known parts weaknesses, etc.) that make them less attractive to me, personally.
For competition, consider stainless (better heat dissipation, longer durability, etc.):
1. 1911 = Kimber Team Match II Stainless (or any other Kimber); absolutely best bang for the buck and requires zero after-purchase gunsmithing or customization (with a possible exception for trigger polishing ($50-$90) to suit your preferences or different sights).
2. Sig P220ST. I love my Sig. Even before Ernie Langdon stormed the 2003 IDPA Nationals with his.
Home Defense = I recommend a DAO or DA/SA to prevent AD's due to a light trigger, especially when you've been jolted out of bed at 3 AM in the dark of night and the adrenaline is rushing, etc...
So Sig P220, Witness, XD, etc. Maybe a Para LDA Hi-Cap if it's legal for you.
CCW / Carry: go for something lighter, like XD or alum Sig, 'cuz you'll probably end up ditching even the best gun in the world if it's too heavy for your belt.
Hope this helps. Be Safe. Have fun!