I'm remiss in not writing about Lolas! (Is the exclamation point part of the name?)
Lolas are prim breasts with a shape that one could argue is more realistic or natural than other prim breasts. To try to give you an idea, here's a photo. (This is with a turtleneck that is not part of the Lolas package.)
They don't have a HUD--one less thing to have to put on and take off. Instead, you control them by touching them, which brings up a menu with options to control size, skin tint, clothing (one can choose from a number of styles of top that go with tops that come with the breasts), and clothing color.
(One nice thing about the size adjustment is that you have a choice of fine, medium, and coarse control: plus or minus one, five, or ten percent. That's a feature I'd like to see more widespread.)
You get a lot of stuff with Lolas, including a package for developing tops that work with them. Nanami has recently announced support for Lolas. If you're considering prim breasts or would like a different shape, by all means give them a look.