Judging by how I saw Carrie handle it, entries would take a lot of practice to get it right. The thing I noticed is that the tanks are hanging low, and thus they can hamper the movement of your legs and arms to help stabilize yourself versus backmount where you do have a lot more range of motion above the water. Once in the water, however, it was just fine.
Carrie did voice an opinion that floating on your back while surface swimming wasn't much of an option, since her rig (a Nomad) didn't handle that very well. But I'm sure more experienced divers would chime in with much more helpful advice.
Peace,
Greg
Surf entry would be easier with cylinders only partially in place. Once submerged, finish hooking things up. Floating on your back is pretty simple. I do it in my modified Nomad.