I go to both HoF and GA quite often. I feel that both are great LFS, I've moved around quite a bit it is quite rare to find not one but two such high quality LFS locally.
In terms of plants, I like the selection in HoF better, Rick is also very helpful if you ever want to special order. Plant price is high, but about the same as GA.
In terms Fish (freshwater), GA definitely have much better price.
For ADA stuffs, HoF definitely have the upper hand in terms of selection. Price is a bit on the high side, but I feel is reasonable for the bigger/heavier stuffs. I got my tanks and stands from them, the experience in both cases were excellent.