I used to dive with a Diva and hated the fit on my body. I also didn't like the jacket style and having so much under my arms and across my front. I recently switched to a Zeagle Zena and am sooooo much happier!
The Zena is a back inflate but since I have no reason to inflate my BC all the way, I don't find that I get thrown on my face when on the surface. I find that adjusting trim and bouyancy with a back inflate is also easier since it automatically puts you in a horizontal position. I've also found that when on the surface I just lean back slightly and "lounge" if I have to wait awhile, and if I do a surface swim, it's going to be on my back anyway.
For me, the super adjustability and comfort of the Zena was the major reason I chose it. I like that it is built using components that I can mix and match as my body changes shape (hopefully as I get slimmer and harder!), and that if I need to have small shoulder straps and a large front panel, I can do it. At this point I wear a medium across the board, but hopefully will need to buy a small front panel in another 6 months.
You can also simply have 2 different bladders for warm and cold water diving and just swap them out depending on what you're doing. I only dive warm, so the smaller bladder is perfect for me.
I can't see myself ever going back to the jacket style BC. I find that the cumberbun around the middle is too wide to adequately keep the BC from riding up on the shoulders when inflated at the surface. Also, because it is so wide, when I would cinch it down enough, it felt constricting across my entire body, and yet still didn't do the job well. I'm really a minimalist type of diver and can't stand having lots of bulk and don't carry lots of doo dads in my pockets etc. The Zena is very minimalist and although you can add pockets, it only comes with one to start.
Quite a few people have said negative things about the Zeagle's ripcord system for ditching weights. Since my husband has a SeaQuest jacket style, I've been able to compare side by side the Zeagle system to his. One thing we all know is that we hope to never need to ditch our weights in an emergency. If that happens, I decided that I won't care that it'll take me 2-5 min. to rethread my ripcord on my Zeagle. Also, I prefer that I put my weights into my pockets through zippers, unlike my husband who uses his release system each time to load and unload weights. He has to make sure that he's snapped his weight pockets back in, or he could lose a $35 pocket.
All that said, a BC is a very personal choice and one you should make carefully. Try on as many styles and types as you can, and even better would be to take them for a dive, even in a swimming pool. The best BC is the one that fits you best.
