A final cnsideration you'll need to make is the availability of units, training and spares.
The Drägers are fairly easily available, as is training for them. Spares too, but unless you have a stocking dealer close by you'll be mail ordering from Germany (which isn't an issue and usually easier and quicker than even most dealers).
OMG has a US distributor in Nevada, but I don't know about the availability of units and parts. OMG also has a new unit, the UBS40, based on but smaller, lighter and less expensive than the Azimuth. Training in the US is available.
Submatix as well as most of the pSCRs are from Germany, without US distribution or dealers, and AFAIK without US based instructors. You'll have to come and visit.
The RB80 is made in the US, and both instructors are based there. But training is by GUE, very high quality if you're willing to put up with it. With their high standards come lots of requirements and a very high price tag (of both unit and training), you'll need to take DIR-F, Tech-1 and Tech-2 to even be eligible for RB training. They try hard to keep the riff-raff off their rigs. :mooner:
On the CCR end, PRISM, Kiss, Meg and Optima are made in the US or Canada, the Inspo and Evo have US and Canadian distribution. The MK15.5 is made in Australia without US representation, the Ouroboros in the UK also without a US distributor.
Give Doug Ebersole here at SB hauler, he's in FL, and an instructor on the Dräger, OMG and Kiss units. If you tend towards CCRs, conatct Curt Bowen from Advanced Diver Magazine, he has another CCR tryout coming up with Inspo/Evo, Kiss, Meg and Optima CCRs.