The more rolls you process in one tank, the more heart-wrenching a "failure" is.
Also, tanks larger than a Nikor Q30 (30 ounce, two rolls of 120) are pretty darned heavy, it's hard to fill and drain them quickly, awkward to agitate them. The weight of the Nikor sheet film tank when full is the biggest problem I have with it.
Also, even by a Q30 tank, properly you should be filling it with developer, and lower the reels in on a lifting rod in the dark. The bigger the tank, the more the risk of filling marks on the film.