You're right, there are alot of great tanks out there. All have their ups and downs. For me, this has turned into a hobby rather quickly. I have bought quite a few tanks (think i am up to 15 when the vapemail gets here), to try to figure out which ones i like the best. What i found, is that i like all of them for different reasons, and right now they are all in the rotation.
Clearomizers:
Top coil:
2 iClear16: Came with my MVP 2.0.
2 VivaNovas: Came with the Smoktech VMax
These give a warmer vape because it has a top coil. I use these with flavors i want warmer, which is mostly tobacco flavors (more like an analog), and some desserts like cinnamon roll, etc to get that hot out of the oven touch to them.
Bottom Coil Clearomizers:
1 Protank
3 Protank II
1 Mini Protank II
These I use for simplicity. Easy to clean, easy to change flavors, easy to fill. The flavors are a little muted, but that is the price you pay for convienence. Also a little muting can be a good thing with really intense menthol/fire and ice type flavors.
Carto tanks:
2 IBTanked
3 ValleyViewVapes.
LOVE the flavor of the carto over a clearo, but reserved for my favorite flavors/ADVs since the carto hold quite a bit of liquid, making it harder to change flavors.
Favorite top coil: Iclear16
Favorite Bottom Coil: Protank II
Favorite Carto tank: IBTanked