If you don't mind an amateur,
I use Apex reg, I found it very easy to breath compared to other reg (tried other's/rental/mine Oceanic, Mares, DiveRite reg) although it may not be a fair comparison since the rest are not in the same price range.
Apex has environmental seal which is good for muck diving and cold diving so I heard.
I use DiveRite Back Floatation and Hubby DiveRite BP, it never gave us any problem at all, comfortable and reliable.
I use Apex reg, I found it very easy to breath compared to other reg (tried other's/rental/mine Oceanic, Mares, DiveRite reg) although it may not be a fair comparison since the rest are not in the same price range.
Apex has environmental seal which is good for muck diving and cold diving so I heard.
I use DiveRite Back Floatation and Hubby DiveRite BP, it never gave us any problem at all, comfortable and reliable.