scotjute,
I have GSF in my pond and I can tell you they fight! JHAP is the ring leader for GSF, but I do have some that are pushing 9 inches and they are fun. I have read they taste pretty good but have never ate one at this point. They are hardy and WILL hold there own in a pond! A lot of guys on this site will frown on you wanting to stock GSF, as they have gotten a bad rep for being the ugly ducking of the sunfish family
but you can't beat it if you can get them for FREE! We caught about 10 this last weekend and my buddy swore he had a bass on one time and it was a 8 inch GSF! They have some fight in them for sure!