I used to dive conventional jacket BCs, but have migrated to BPW full time for fun and DM work for open water. I would recommend a single harness as opposed to the "comfort" or "elite" split harness configuration. Believe it or not, the single harness is easier to use and slightly faster to get in and out of the rig.
For pool sessions I still use a rental BC - the chlorine will take its toll over time on any gear, so I borrow gear from the shop for pool sessions.
Should you go the BPW route, please be advised there are currently 3 different materials for the plate: stainless steel, aluminum and composite (heavier to lighter). The size wing will depend on what size tank(s) you will be using and it is not uncommon for you to eventually have two wings.
Most of the instructors that I work with are currently on a BPW system, while most of the OW students will be in a conventional jacket BCD which is rented from the shop. As other posts have mentioned, it would be a good idea to align your gear with whatever the shop is selling, after all you will be a reference for newcomers.
Hope this helps, and let us know if you have any questions