You can use any brand of peat moss you like, however there are some things to watch out for..
Make sure not to puchase brands that have been fertilized. They can overload your tanks npk values. (Miracle-Gro)
Some brands of peat are more coarse than others. So that can help change the look of your BG. For example Whitney Farms tends to have larger particles vs. the extra fine found in larger 2.0 cuft bales. So it depends on the look you want.
I've seen ppl use straight coconut pith or 50/50 pith/peat. I've heard some ppl say that the pith is alkaline, while peat is slightly acidic also. Personally I use straight peat because it seems to last much longer. Pith is durable too, but if you're looking at years of use peat bogs have been around forever..
For an added look you can also silocone actual chopped coconut shell (1/2" chunks sold as substrate) or fir bark into BG's.
Hope this helps.
Rogue-Hawk.