To put it simply, the less interior cells you have, the more connected and open everything is. However, the more interior cells you have, generally improves performance.
I don't get your poll. Is it about interior/exterior cells, like it claims to be? In which case, what's the problem? They are basically a way to partition the game space into discrete chunks, and have specific benefits and drawbacks in regard to how the game engine deals with physics, AI, path finding, memory usage, line-of-sight calculations and so on.
Or is it about the method of transition between cells (which can be a loading screen, like in Morrowind, Oblivion and Fallout, a seamless transition with the help of a portal, and one of a bunch of variants of those two methods)? Because
this doesn't depend on whether the interiors of a building are in a separate cell or not, for example ...