@VESmedic listening to your bass clips in the Morin thread got me thinking. IMO the C+ does suck with tunings below about D standard, it just falls apart. It's in E and Eb where it's so hard to beat. Odd, but that's my experience. If a guy lives in a 7/8 string modern metal world then yeah, I would steer very clear of any vintage Mark. The IV does better here & the V possibly does the best in the Mark lineup at that low chuggy stuff. ...And, a Recto or a 5150 will smoke any Mark down there as will a ton of other modern metal amps that are designed for that register.
It's all about the right tool for the job- just like I love a good Greenback, but not for chuggy metal. If that was all I played I would think they sucked. It's like how IRs have gotten very good for recording but they still sound sterile cranked in the room. It's also like how Fricker's perspective is so tunnel vision on close mic recording high gain tones for mixes, and he refuses to give credence to any other musical angle or perspective- of which there are many. Oh, wait...