for booking hotel rooms normally using TRIVAGO - comes up with decent offers etc.
A bit of a surprise then that I double checked a particular notel (yes, 4 star in a European Capital City) - Trivago.es gets me a rate of 32 euros and Agoda gives me a rate of 21 euros (which is a total knock-down price).
So it pays not to relay too much on one particular site ... and keep checking a bit.