I love my several TC100W but it's not "new" anymore, but it's crazy cheap, very solid, for me, it's virtually flawless and the best mod I've ever had (and why I now have several)... I've only had one that started acting funny after a few months, and it's in the being exchanged process at this time, but the several others we have have been great even after over a year for a few of them. (edit: just though I'd mention that my wife and my daughter have dropped theirs so many times it's scary, but yet, the mods are still working great - but are fairly dinged up)
The pros for this mod:
- Reliable/very solid
- sleak, fits in back pocket easily and comfortably
- very comfortable in hand
- squeeze trigger
- parallel (100W but goes up to 120W with the firmware upgrade)
- amazing battery life (outdoes every dual battery mods we have easily)
- reliable on-board charging
- does just about every mode possible (TC all metals, memory settings, bypass, etc.)
- physical trigger lock
- nice modern look
- can function on a single battery if needed (at reduced wattage of course)
- controls: one of the best interface, the extra mode button instead of the multi-clicks to switch stuff is beyond "better".
- Magnetic door only, no stub or mechanism to break.
The cons
- because it's so sleak/slim, tanks over 23mm will stick out a bit
The Predator is a great mod also... but there's been some issues noted with the 510 pin coming out, but we have 2 and after a few weeks, they've been fine. It's possibly a first batch issue. Compared to the TC100W, it's like a thicker brother (so can handle larger tanks) but has just about everything the same for the pros except that it's not a parallel, goes over 200W and a much bigger/fancier screen (but not magnetic doors). The battery life is also less.
These two mods are very inexpensive....so it's a win-win, worse case, if you have 100$, then get one of each or two of one.
There's of course the Alien that you should check too (I don't have one so can't say much about it). It's well loved by many, also inexpensive and aside a few issues with paint for the earlier batches, and a few mention of board dying for some people, it's been a fairly solid mod.
Sadly, for your choices, I'd never get an RX, just never liked them, both how they look or all the problems people had with them. Not a fan of Pionner mods either, while some will vouch for them, I find they seem cheap to me. For the VGod, similar, never impressed me, I'm not a big fan of the square box form factor with the "face" console look, just too basic average looking.
And honestly, since squeeze triggers, buttons are an absolute pain to use compared... like "what is this, the middle-ages?" bad.