I've got a whole box full of mods similar to those you listed, all bought trying to save some money. Do yourself a favor and try to make do with what you have until you've saved enough to get something worth spending your money on. I use three mods daily now a GGTS, Provari Mini and a Vamo. The first two are built better but the Vamo has some really nice features that they don't even when the GG is Kicked. The Vamo is really nice if you are into rebuildables. You can check your resistance on it but you really don't need to if you have it set for a certain wattage. When it comes to making coils you don't have to get them exactly right, just get them in the neighborhood and it'll dial them in for you. If you look around there are co-ops being run on these or you can order from China if you want to save some cash. For $50 it's got to be the best bang-for-your-buck in the vaping world. Here's a review of it if you haven't seen it:
http://www.e-cigarette-forum.com/forum/e-cigarette-video-reviews/358779-pbusardo-review-vamo.html
I agree, save your money! I almost bought a gripper, then I handled one at a B&M, it was decent, until he wanted $30 for the silly thing!
I've heard a lot of good things of the Vamo and Zmax, I haven't used either though so I can't say for sure. I bit the bullet and bought a Provari mini, everything else is collecting dust right now! It's not that it's that much better to vape, it's just built well, and it JUST WORKS! Period!
You don't have to spend that kind of money though, as I said, the Vamo and Zmax can be found for good prices with some searching. Even a SB is a good choice, then add an extension and a Kick later on. I might sell my Lava tube some day, but my BB will NEVER go anywhere! It's just built too well, and it WORKS as well!