I just bought an RX-V3900 to replace a Marantz SR7001 and couldn't be more satisfied.
This is my first Yamaha and what suprised me the most was how easy the unit is to setup and operate. Everything just worked without a glitch.
From the YPAO room setup feature, getting my music through the networking function, using internet radio, upgrading firmware, learning the soundfield features...everything worked effortlessly without having to runto the internet to search for answers to get it working correctly.
I have no knowledge of the 2500 so I can't comment about comparing sound quality but I will tell you I've never been as satisfied with my system as I am with my current setup. Past receivers have been the Marant SR7001, Onkyo 805, Denon, and an Anthem AVM30 (the best I've had for music but never satisfied with HT duties).