Guys, if you are going to recommend the Posiedens, especially the older ones, at least tell him the drawbacks.
Bell47, you will hear quite a lot of the same names coming up.
1. ScubaPro
2. Apeks
3. Aqualung (less)
4. Cave regs like Dive Rite, Salvo, Oxycheq, and maybe even OMS since you're up north.
5. Posieden
Each have their benefits and drawbacks. For innstance the Posieden regs have many specialized parts, are often difficult to find service for, require a custom hose in the case of the older models, and cannot be taken apart underwater if they get fouled. They also purge differently than most other regs, even the newer models, so can cause quite a shock for the uninitiated.
The ScubaPro regs are often piston based and this can be problematic in frigid waters. They do have some cold water models, so be mindful of that if you intend to dive very cold water.
The Apeks regs are generally excellent, but some models like the DS4 seemed to have quirks when used very deep. Check into that.
The Cave companies usually have regs made to spec for them by overseas companies and are often more similar than different. Additionally, many will sell service kits to owners so they can do their own maintenance. The larger companies won't do this.
I'm sure you'll get many fine recommendations, but be sure to do some research on the regs before purchasing.