I Just received my Jetbeam III Pro (not ultra)
I really wanted something that used a 18650 and regulated, and from my understanding the ultra is not regulated with the 18650 only 123's as with most other light that use either battery.
The other factor Ive never really like throw lights but after playing with my Jet Pro I do kinda like it, Low is low enough for up close work, but doesn't really matter as I have a few lights on me. The Ultra should have more throw than the Pro.
Also I never had a really good comparison of the Jetbeams size, After I got mine I was glad I didnt get the Ultra because the Pro is probaly my EDC size limit.
Hopefully youll love yours, Im consideing another Jetbeam, They are really nicely made.