Glocks and Sigs are both good weapons. But being a Sig fan, especially of the P220 this weapon would be my first choice.
One is no more reliable than the other under realistic conditions. And neither is "perfect," as no gun is.
The model 21 does have more fire power in standard 10+1 configuration. But you can buy 10 round mags for the P220, so I guess that arguement goes right out the window, unless you want to spend $100! on those pre-ban 13 rounders. NOT ME...
The SIG IMHO does have a much smoother (perhaps the smoothest of any DA/SA pistol)trigger pull, very little felt recoil, narrower single stack frame that is ideal for smaller and medium size hands.
The Glock model 21 is a rather large semi-auto handgun that is not ideal for smaller hands. If Glock is what you really want, and you don't have big hands, I think that the model 30 .45ACP would be a much better choice.
Personally I do not like Glocks because of the "ROUGH" DAO triggers on them, and there less than elegant design. But that is just me. Many people swear by them!
I would say handle both weapons and decide for yourself. I think you will like the P220 as it is a very hard pistol to beat! I have walked into many gun shops to have the sales people say that it is "the finest out of the box weapon in their inventory!"
But again, decide for yourself...
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SURE SHOT
[This message has been edited by James Montes (edited November 14, 1999).]