I may sound like a broken record, but I have a Tripower (2 actually, one new and one old), and I really like it. So far, it is the best unmagnified sight I have used. The chevron is very easy to pick up, and feels subjectively quicker than and Eotech or Aimpoint's reticle (but this is subjective, and others probably will beg to differ). Overall, it's size is about the same as an Aimpoint, but the mounting portion of it is further forward, which means it hangs further aft of whatever mount you are using than an Aimpoint would.
The tritium is always "on," but the reticle is not really visible to the naked eye until close to total darkness (and letting your eyes adjust). If you have NVG's, then the tritium is supposed to light the chevron just about right.
What are they worth? I've seen them sell for $499-$529 new. Be aware that there are 2 generations of earlier Tripowers that have partial-plastic bodies, a tube for accepting Cyalume sticks (for a fourth source to light the reticle), and they are also known to have problems like having a "shadow" chevron show up when you look at the reticle sometimes.
I have one of the 2nd gen models, and I have seen the shadow reticle a couple of times, but for the most part it works pretty well. I think it's reticle is not as bright as the new-gen model's in most light (using the fiber optic to light the reticle- and that's been redisgned in the new-gen Tripower too).