Bel Canto REF500M Monoblock vs Jeff Rowland model 201 monoblock

Sorry, my modest system will be using a Jolida fusion tube pre.
Speakers are Silverline Audio Sonatina MK IV's

I can heartily endorse the Bel Cantos. I've had them for 2 1/2 years and love them.  They are dynamic and detailed, strong bass and natural high end.  They easily drive my Dali Mentor 6s in a large open room with 18 ft ceilings. I use Nordost Heimdall II ICs and power cables on my Marantz 8003 CD player and Cambridge 851N network player, which also acts as preamp. I also use Spotify and run downloads through the Cambridge. The BCs stay on all the time and stay cool.  I tried Nordost power cables on the monoblocks and frankly could not hear a difference (though they made a huge difference on the Marantz and Cambridge).  I have Acoustic Zen Hologram II speaker cables and I have AZ Tsunami power cables on the BCs but I intend to test them against the stock cables. I just don't think they need anything special for power cables. These amps replaced BC 300Ms and before that B&K and Adcom amps. All powerful, but the 500s were far and away the best.  More musical. Never had the urge to upgrade the 500s.  Good luck whichever way you go.