I am using this plan since October, 2010. Earlier I was having BSNL FN 500 Combo (1.5 GB limit), but now I am on FN 600.
Earlier you had to rest modem once before 8 am, just switch it off. But these days I have noticed, connection session automatically resets at 8 am.
I am not a heavy downloader. I just download 1 movie, that too not on daily basis. I mostly download academic lectures and that's not much big stuff.