i have been in mansarovar hotel last year in mid of Dec 2008.
the best thing i liked was it's meal and breakfast, specifically that Paneer parathas. I was on third floor and quite good evironment i found there. services was good enough to attract once again but with some improvement. Since it is opposite to Cantt railway station Varanasi and adjacent to Bus station and on main road, horn and whistle whole night can disturb your sleep a bit, but OK has some benefits as well eg for good connectivity. vary good environment for family accommodation.