From a progression point of view I think tanks are better. Tanks don't require a brand new mod to work, and they do the same exact thing - feed the carto. I think its all personal preference but tanks just seem easier and more efficient. Im speaking of course of a good tank, some tanks suck. My J-tank is amazing, I have 3 of them. As for portability, I have to give it to the smaller bottom feeders. I never leave the house with a tank, just packup a small box or ego battery with a very very large ego carto.