I did not experience such a drain with any build of Mitakuuluu. In fact, with or without this app, the idle battery consumption is very low : about 2 - 4 percentage points during the night.

I would say it's quite impressive, Wazzap for the N9 was not so efficient.
Beside showing the quality of Mitakuuluu, I think theses good results show mainly the quality of Sailfish: very efficient power management and sane way to connect to the internet.