Boulder 500AE compares to New Models

Any Boulder experts out there?

How does the Boulder 500Ae compare to the current models like the 850 and 1060?

Are they similar or totally different animals.

How important is running balanced on a Boulder amp?

Scott, can't answer your questions but can offer one bit of advice. Pay attention to the impedance matching with your line stage/preamp. Years ago I tried a pair of Boulder 500AEs but their 10K load didn't work well with my tube preamp. I didn't realize the reason at the time so sold the Boulders due to disappointing sonics. Unfortunately I never heard their full potential.