I was looking at the Jetstream 1, but I decided to go with the Deltec for one big reason: the Jetstream was a hassle to change/add media. The Deltec is the best design for this function I've seen: a quarter twist and the top comes loose (very easily) and you have full access to the media chamber. Other then that, the reverse flow, the larger media chamber, and the more elegant design made Deltec the clear winner. They were about the same price when I was shopping for my Ca reactor last year.
Precision Marine makes very solid products of excellent acrylic construction. However, for the price, I really would still much rather get a Deltec. Thumbscrews are a huge no-no for me.
All in all, the modern day reactors are all pretty good. It comes down to features and convenience for me, and that is why I chose Deltec.
People over here say the Schuran calcium reactors are hyper-efficient, beating anything else, but run best if fed by a peristaltic pump. Given they are pretty expensive (added to the cost of the Schuran itself, which I assume is even more expensive in the US), I'd go for something local, or the Deltec as Len suggests.
I run the jetstream 1 and love it. It is very effective and the large coral media is way better then classic media. You just top off as needed and adding media every few months is really a non issue for me.
I also feed it with a aqualifter with no problems, so that was a smal added cost, IIRC $12.99
The reactor is solid, hangs on the wall and recycles the c02 very well.