I've been rocking this T-Priv for like 2 years at this point, and I've loved it so much I hadn't really bothered purchasing any new box mods since I got it.
My original reasons for getting it was pretty simple: I wanted something with a full firing bar. So far, with pretty heavy use over these 2 years, the bar has held up extremely well. It's not super sensitive, so you don't have to worry about it accidentally firing if you have it in your pocket, but it doesn't take a ton of pressure to fire it in the hand. I love it. Also makes it extremely easy to use in either hand, and its easy to fire using either just your thumb, or all 4 fingers.
The other bonus for this mod that made me want it was the fact that it lights up. It's quite fun to use at night when you're driving. And surprisingly, I didn't really notice much of a difference in battery life when using the LED's/having them turned off.
Everything else about this mod is pretty 'standard' as far as being able to set temps and things like that. All in all it's been an extremely reliable box mod for me, and worth every penny.