Mr. Cody, as usual, makes some good valid points. My main concern with GS is his number 4, tying up biomass. I have not had problems with BG or RES laying enough eggs to reproduce even with the GS present. My LMB were not really large/old enough last year to have been expected to spawn (they didn't).
The GS are horrible bait stealers while you are worm fishing, but kind of fun to play with. I have even caught them on small spinner baits.
My final opinion on GS in a combined BG-RES-LMB emphasis pond will have to wait a couple of years (hindsight always 20-20).