The Octo+ is somewhat different from other integrated power inflators/backup air source devices. It separates the air in the wing from the air supplied to the regulator. Generally speaking, you won't be breathing your wing (and whatever critters are growing in there) with the Octo+. The downside to this, if it is one, is that the manual inflation port is NOT the mouthpiece but a small hole on the side of the housing. This works fine but is counterintuitive to some people and takes some getting used to. Practice using this as you may need to disconnect your power inflator hose in the event of a failure.
As with all integrated units, fine tuning bouyancy while using the regulator feature is difficult. You pretty much have to use the pull dump on the wing (really sluggish on Zeagles - their weakest point, IMHO) unless you are in a head down (odd position in an emergency) or remove the Octo+ from your mouth to raise it above your head. This is the facet I'm most uncomfortable with. Generally, I would plan to dump all air in the wing and slowly swim up using the Octo+ in an emergency. Careful attention to weighting when diving wet, is, IMHO much more critical with an integrated inflator/reg than with stand alone units.
On the positive side, the Octo+ is a "real" regulator (go to an Apeks page and check out the Sentinel). I have had no free flow or other problems with mine (I have two) but I always have them serviced annually as they are regulators. Dee's recommendation of a long hose on the primary is a good one, I'm planning to order one and try a 4 or 5 foot hose on the primary. You will donate your primary, practice this with a regular buddy.
I switched from a traditional backup for two reasons: One, it kept coming unclipped and dangling (I hate danglies); two, I like the "one less hose" feeling. I may try a bungeed backup in the future but am pretty happy now. My usual buddy is my daughter, she uses a Seaquest Diva/combined power inflator/backup rig. We've practiced handoffs of the primary and are careful to point out this fact to others we dive with. You might even consider getting a yellow hose and faceplate (if available) for your primary so someone won't try to grab the Octo+ and use it and get into further difficulty. Particularly if you don't dive with a consistent partner.
In my limited experience, 53 dives, I've found, as with most things in life, compromises are necessary. I think the Octo+ is a reasonable one in recreational open water environments. Neither of us do wreck penetration or overhead and tend to stay above 80' (Check out DAN's latest report on DCS and you'll see why).
In sum - try it out if you can and practice using it if you choose it.
All of this being said, if we had a stocking Halcyon dealer in our area, we both might be looking at BP/wings with bungeed backups. Absent that and any local user support/advice for use/setup/adjustment of the BP/wing configuration, we went with more traditional BC's (Zeagel and Diva LX).
Best wishes and my apologies for the long response.
Bill
