I've got a Sigelei, a Cloupor Hana DNA 30 clone, and two Reo Grands.
The Reos have their place, which is usually on the go. They are just so convenient to use, especially when driving. I've really dumbed them both down by using shorty cartomizers and 306 atomizers. Just really simple to use with very little fuss. Loving the low-tech.
Of the two other box mods, I MUCH prefer the Sigelei 100w mod over the Clouper. It's not even the power or dual 18650s of the Sigelei (which are nice) but the Cloupor is quirky. It randomly turns on and off, so the battery slowly discharges even if it's just sitting on the table not being used. Also, the power setting changes by itself, slowly dropping with use. If I set it for 15w and start vaping, I'll check the screen and it will say 14.9, then 14.8...It may stop there or continue to drop - it's completely random.
Anyway, I'm sorry I wasted my money on the Cloupor. I'm not sure that they have since worked out the quirks, but I wouldn't buy another of their mods. The Sigelei on the other hand has been rock steady. Super powerful and looooong battery life. I seriously doubt that I will have a need for 100w (yeah, don't quote me on that 6 months from now

) but it's nice to know it's available.
Anyway, my advice would be to get the best name brand mod you can afford. If I were buying a DNA mod I would very likely get a genuine Hana. I wasted 70 bucks on the Cloupor, so I'm nearly half way there already and have a crappy clone. Don't make the same mistake I did - as they say on the gun forums: buy once, cry once.