I'm only following one, and that's because the work is good, and the person is on my flist. I tend not to follow wips because invariably, RL intrudes and the story rarely gets finished. Or the writing is uneven and the continuity of action is lacking.

Personally, I'd prefer if the author just did one big piece and post it out there, it's a better read, in the sense that you have one coherent whole. Besides, following WIPs calls for a fandom committment that I can't give anymore.