I can't speak about the Inspiration, but I do own and dive the Optima. The Optima is a great rebreather from a reputable company. It is fully electronic and can be used for both recreational and deeper technical diving.
One of the main selling points for me was the fact that it is manufactured by a company that I was very familiar with. I personally used lots of Dive Rite products for technical diving and have always been pleased with the design and quality of their products.
The Optima also uses the EAC catridge as a scrubber. You will find that many rebreather divers do not like the Optima because of that fact; however, most divers making those comments have never actually used the EAC's, so they are not speaking from experience. The EAC's are extremely convenient to use. Instead of having to pack a scrubber, you just drop in a new cartridge and you are set. The use of the EAC's also ensures that your scrubber function is always consistent, because it is not depentent on you personally packing the scrubber material. I know several other divers who use the Optima for warm water dives and most of us have been exchanging the cartridge every four hours or so, but upon inspection of the cartridge after we remove it, it appears as though the cartridge is only about 1/2 to 3/4 used, but four hours seems to be a nice conservative point to exchange it.
One other point, unlike open-circuit, rebreathers require much more maintenance. Furthermore, there is always fine tuning and minor glitches that must be addressed; therefore, if I were you, I would not buy a unit that you did not have support close at hand. I live a few miles from Fill Express (a.k.a.:
Dive Rite Express and
Rebreather Express - Rebreathers and Accessories. Full Warranties. Free Shipping.). There have been times when I have had to go by their shop for minor troubleshooting with the rebreather - I can't imagine owning a unit and not having support close at hand.
I hope some of this information helps you make a decision.
Good luck and safe diving!