I just put a set of 45-105 Round Core Boomers on my '77 MSB. The tension is just below regular Boomers; they feel like the tension of an old, played in set. The Round Core doesn't seem to buzz easily on the frets like a light gauge can. They have some nice midrange content and grunt right out of the box---maybe a bit more of this than regular Boomers. Maybe the added flexibility is eliciting a different reaction from the pickups; they're pretty ballsy. Overall, a beefy, clear sound with nice sustain. Bottom line...the Round Cores are sort of like regular Boomers, have a meaty tone, and are definitely easier to play and get around on than regular Boomers. I like them a lot.