We've completed our stay, and I have mixed thoughts. We only paid £20.12 for the night, and were upgraded to an Exec King. For the price we paid and the excellent location this was great value.
However, normal prices for a weekend night booked online seem to run north of £100. I'm not sure I'd be happy paying that. The room was clean but tired - the decor was more old style HI than modern CP. Definitely the most dated rooms I've seen in a UK CP.
If I wanted to stay in Cambridge again, I would be tempted to stay at the new HIX at Whittlesford Parkway station and then take the 10 min train ride.