i have the bonds, lovable and topsecretmaternity singlets.
i like the TSM for feeding because they do not expose your whole breast, unlike bonds and maternity, where you undo the to and pull it down to expose boob to feed bub. the TSM keeps the top of your boob covered. but i prefer the fabric and the fit of bonds and lovable best. as far as fit goes i prefer bonds, and i like that they are padded as they give the breast a nice shape, i find that once you put a breast pad in, with the other tops, you get a funny lumpy look to the breast which i hate. with bonds you get a nice smooth shape :-)
none of them offer a lot of suport, today i went for a long walk with bub and was wearing the TSM top and my boobs were jiggling as i walked and i thought, great, now i will have double the saggy boobs, due to breastfeeding AND exercising without support.

incidentally, has anyone come across any breastfeeding sports bras?!

ETA the lovable ones are the most comfy in terms of fabric and i sleep in them.