I am looking for the best pistol overall for target shooting, and home defense out of the ones posted.
Glock 21c 45auto
Beretta 90-two Type F Cal.40 S&W
Colt Government 1991 .45 ACP
If U want a Glock 21, I would recommend against the comped version. Truthfully, out of those models, probably the 1911 (doesn't have to be a Colt, U can get a nice S&W or Kimber - probably more features, for the same price). The Beretta would be next.
Instead of the Glock 21, U should look at the Glock 34 or Glock 35, depending on your caliber. Realize the 9mm is 1/2 the cost of .45ACP ammo. I have a Glock 34, and it makes an awesome target gun. It is also my night stand gun.