I switched from a jacket BCD to a BP/W and would not go back. The advantage I like the most is that the Hogarthian BP&W rig is so much easier to rinse, dry and pack than a jacket! I also appreciate the reduced drag in water and much less mess with buckles and rims. A well thought through and tested system where to store what - the prime light, the backup light, the SPG etc. And I can modify it, if I want to dive a double tank set. Otherwise the jacket was ok, too. Not such a big differnece in horizontal trim as I expected.
As to which BP&W to choose - after extensive reading I chose the Deep Sea Supply as the best quality for the price and a great customer support. It's also very simple to assamble and disassamble and doesn't need a single tank adapter - the tank is some 2'' closer to your back. If you chose a DSS rig, consider also the weight plates and the harness glider.
Have a look at Zeagle Express Tech - it's something inbetween. I read very good reviews of it, and it's light, simple, inexpensive and fits most sizes. Great for traveling. Some say, it's not good for cold water diving, though, because it's so lightweight for a thick wetsuit or dry suit with a lot of buoyancy.
Good luck!