The VT-500 is based on the VT pedal rather than the BDDI/RBI. That said: I own both the RBI and the VT rackmount, and the VT can sound similar to the RBI if you push the Character knob left of noon which adds mid scoop similar to the RBI.
My favorite feature of the RBI is the Presence control. It adds high-end sparkle to the tube emulation, which sounds amazing with my tweeterless Bergantino NV610. I also love the VT rackmount through that cab (or any other).
Big picture: the VT and RBI have slightly different tonal flavors, but both have the SansAmp tube emulation magic, so I believe you will like the new VT amp. The Character control is a lot of fun.