Ivanova, what's not to like?
I watched it pretty consistently thorugh the first two seasons but stopped after the shadow spacecraft had turned up and starting causing trouble. I really liked where it was going but I didn't watch it for a long time (2nd child born) and started again towards the end of season 4. At which point I had no clue what was going on and I stopped altogether. I've always figured I would go back & start from the beginning.