The Jet 1 Pro is a great light. I run Eneloop NiMH's in mine. Bought it at Bugout Gear for $80 back in February.
They have since come out with some confusingly named derivatives with better regulation including a feature that permits a variable setting on the lower levels.
It is very bright overall, and throws a beam that will compare with other lights up to 2 CR123 (Romisen RC-F4, Surfire). I think the original Jet 1 Pro was only available in one big lot - similar to the way the even more pompously named "Defender Infinity" was. i.e., if you ordered while it was on super special pre-order, you got one. Then for months it was unavailable, and you could discuss how much better it it was than anyone elses light, but could not buy one.
I have since paid $30 from Kai Domain for a Jetbeam C-LE V2, which was a better value. This one is also discontinued. It is not nearly as bright on high, but is a good performer overall and has better battery life. It may even be my favorite.
Both these single AA lights have beautiful machining and finishing. I'm sold on the 1 x AA format using Eneloops as totally practical, handy, and strong performers. No more CR123's for me - these will fit in your front pocket with ease. Unless you are doing searchlight tasks, they produce plenty of light. I change batteries every couple of weeks, and either one of them would give me hours of good output on an alkaline (in a pinch) using the lowest setting.
I don't mean to disparage the Nitecore NDI, I might very well have bought one if my buy mode had not been in the long period after the originals shipped when it was in shadowlight (one you couldn't get) mode. I have not handled one.
Looking back, $80 is still a lot, but the Jet 1 Pro is a very strong performer. If you find a good deal on a 1 x AA Jetbeam, get it.