For the d2 it's a straightforward device... I've been using it for the past 2 months plus... It's simple as.. No frills TC in ni200 and ti, fires down to 0.2 solid build, good firing chip and never let's me down...
Sigelei 75w tc I don't own it... Yet.... I got the 150w TC and also works like a charm... No frills, good build firing chip abit of a slower ramp up then the d2 but it's a non issue actually... If the 75w is anything like the 150w then it's a safe buy....
The evic mini, mainly it's for the wider range of TC wires in a small package and upgradable software....
Any of these 3 you won't regret... Bored maybe.... But def no regrets....