There is definitely a water temp range that calls for a 7mm and not a drysuit, IMO.
I dislike body glove since they moved production from california to offshore; I think that almost every suit they make will need at least one seam repair (free, but a pain) and the quality of their neoprene isn't great. It's tough, but gets stiff and loses warmth, probably the opposite end of the scale from the stretchy/fluffy neoprene that's so great when new but gets thin and torn with time.
My wife has a 3mm bare that really impresses me. It has many panels in it and she says it's really comfortable. I'd definitely try a bare if you're buying off the rack. Look for stuff with a lot of panels, especially if it's not the stretchy neoprene. Another knock against body glove, their suits don't have many panels, they are really basic cuts.
Custom is, of course, a good way to go, not just for cut but also so you get the neoprene you want. Aquaflite has some tough, thick stuff that could be 10mm, I can't remember, that a lot of serious SoCal lobster hunters wear. You can also go skin-in, like a freediver wears, that's warmer and takes a spray bottle of conditioner to put on.
There is also something to be said for buying a cheap suit off the rack frequently. A new, soft, fluffy coat of neoprene is really nice.