by sa do you mean the xd or one of the 9mm 1911's?
they are similar in the fact that they are striker fired, no external safeties( by this i mean thumb safeties, polymer framed,and come in a variety of frame sizes and calibers, and great all around handguns and a great buy. lots of acessories and cheap magazines for the both of them.
welcome to THR
check out this thread i made earlier in relation to the xd.
http://www.thehighroad.org/showthread.php?t=222606
If you are posting about the xd then i would most definetly go with the xd. but that is because the glock just dosen't fit me. I can't get into the grip angle of the glock, and the ergonaomics just don't do it for me.
the xd has metal sights unlike the glock, which glock's factory u shape sights i hate.
the xd has a metal guide rod unlike the glock
the xd has a metal trigger unlike the glock.
I dislike the glocks finger groves and blockyness
it always seems that my hand is canted foward in an uncomfortable postion with the glock.
the trigger is all around better for me on the xd than the glock
hey and everyone knows that the xd looks pretier than the glock!
SA has earned my respect!
by now the accessories that can be had for the glock can now be had for the xd which wasn't the case some time ago, not all but a great majority. which was a big plus for the glock owners before, it is now a pretty level playing field!
these are a few reasons but not nearly all the reasons i love the xd over the gock, and yes i have owned and shot both alot so i do know what i am talking about. this is me and my personal prefferences and by no means am i talking for everyone. both are fine weapons and would serve you well, but i say go for the xd!