well, its really a matter of whether you like the top coil or bottom coils.... (Iclear 16/30 and 30s are top coils, 30bs are bottoms.) Top coils for some folks give a better flavor, and are a warmer vape, but they can have wicking issues. Bottoms give a cooler vape, some folks complain of a muted flavor and have their own issues (flooding).
Best all around option in my opinion, are carto tanks:
Baditude's how to carto tank blog. Pretty much explains all you'd ever need to know about cartotanks.
IBTanked - Get Tanked With Us! is a great place to get excellent pyrex tanks for cartotanks, but if you're just looking to try one, then I'd say to try any of the major vendor websites. They should all have them.
I myself on ego/ 510 devices run cartotanks, Vivinovas (top coil, easily rebuildable too!) and Kanger PT2/ Aerotanks. Depends on the joos for me.
Hope that helps, and enjoy the MVP!