So is the G21 the largest of the Glocks that you mentioned here? Is that the one you would buy if you were not concerned about it being a conceal and carry? And do you know how many magazines the Glocks usually come with (just 1 or is it 2?)?
I think they all come with 2, but I bought my only one used, so I'm not sure. The G21 in 45 and the G20 in 10mm are the largest Glocks (thickest and bulkiest)and share the same size frame. Ted Nugent hunts with a 6 inch barrel on his G20. Dropped a pig at 100yards with one shot.
The G21 has a big grip. The 40 and 9mm Glocks fit my hand better, so it took some intense retraining with the new grip to fire it quickly and well, but it can be done. As much as I love the 45, I'll probably switch to 40 or 357 sig if I buy another defensive Glock. I'd get a mid size like the G23 for carry, and a long barrel like theG24 or G35 for the house.
If you consider the Sprinfield XD, make certain that you get the new Melonite finish. The first few runs of those guns had something different that was prone to surface rust. The XD is on my list for good ones too.
This is the 40 cal Glock family (from smallest to largest), so you can see the size differences.
They, along with all the XDs, have polygonal rifling that requires the use of jacketed bullets instead of regular lead. No biggie.
G27
G23
G22
G35
G24
The G24 was the original long barrel 40, and the G35 is the shortened version to accomodate certain competition rules regarding overall size.
One thing that I don't like about the G24 and G35 is that the slide's top is cut out for the barrel ports even if you get a non-ported barrel. You don't want a ported barrel on a defensive gun that you may have to fire fromstrange positions that might send hot gas and lead splinters into your face.