I use the "Original Belly Band" (quality: OK) with a KelTec P3AT, I find anything much bulkier (i.e. j-frame and up) a bit more difficult to conceal. With the larger guns, I like tuckables like the Crossbreed. But like any holster/system, it's largely a matter of your size/shape, the guns size and your choice of clothing.
I only use the bellyband for very deep concealment with more fitted clothes.