I started off with the Fenix L1 P... and I was wow'd. Then along came the Nightcore DI, and I was sold on that; after all, forward clicky, rugged design, multi mode... what isn't to like? Well, I lost it. Dammit. So I replaced it with a JETBeam JET-1 Pro IBS-- just came in the mail today, and while I cannot speak for long-term use, I already see the benefit of the UI over the NDI. See, the NDI was great for "showing off" to the non-flashaholics; I'd start off in high, then switch to low... lest anyone see me start on low and think that's it? Well, the head started acting up-- I'd twist off for low, and the light would enter strobe right before low came on, and I'd have to do the twist again to get it back into high. That's fine if you're sitting in an office cubicle, but not in the back of an ambulance on a trauma where you're checking pupils one moment, then searching in the dark for other patients the next-- believe me, if there is a time that you don't want to be fussing with twisting a flashlight head while wearing sweat-filled blood-covered gloves, that would be it. For that reason, I love the JET-1 Pro IBS. Long-term use may prove me wrong, but right now I see it as a great multi-mode EDC light that is a lot less prone to rolling than the Fenix or NDI, and it already comes with a pocket clip.
Everyone is entitled to an opinion here... I'm not trying to trash someone's favorite light, I'm just telling you what works for me.