I would take a look online at some of the vendors here, and then maybe check their vendor pages to see if they have many complaints or not. There is also a subforum... somewhere... called "Negative Reviews of Suppliers," and often you can find certain vendors there and concerns and how they are/are not resolved.
Depending on how quickly you want your new gear may also help you rule out for example, many of the China-based suppliers, which can offer great deals but slower shipping times. But the option of star suppliers is a good one too, and I'd say that if you are buying very new to you gear, you want to be sure that you get good vendor support in case of a problem or warranty issue (just generally, not necessarily directed at Smok the mag kit is getting pretty good reviews so far).
Best of luck,
Anna