hehe...I did a survey on sidearms before some over zealous mod decided they didn't like my choice of topics and deleted the post....and it was between Glocks and 1911's as far as popularity.
Personally I have an KWA M9 PTP, a Tanaka P8, a Tanaka USP40 and KWA Sig226 PPTP.. There is no doubt that the one that feels best in my hand is the P8. With that said as far build quality and parts availability I would go with a KSC. And try to go with a metal slide if you intend to use propane. I have seen too many ABS slide guns blow off the frame when using propane.
A Glock 17 is really the only Glock model used by combat forces (if that matters to you) and there is lots of parts available from several manufacturers...
my 2 cents worth..,...
Semper Primus: Always First