If you like building Herakles just came out with a baller 25mm RTA.
The V2 is literally just a Herakles Plus with less capacity and no top airflow. If you don't mind a low profile 2ml tank, get the V2, if you want more capacity and more airflow, get the Plus.
The V8 is nice, it has a FUCK load of different coil options, but I don't like any of them enough to warrant using it. I'm a rebuildable guy at heart anyway. The V2 is very TPDish.