Sorry it took so long to respond. Long story short, I decided to hold on to the RedWine Isabella and let Matt Rotunda (a real gem in the audio industry who was a joy to work with... you're in luck if he covers your area) of Pitch Perfect Audio have back the Monbrison.
Upon immediate listen, the Shindo Monbrison had a larger soundstage, more bass kick, and possibly a more seductive midrange (and a low level of sibilance that was only apparent when directly compared to the RedWine). Upon longer listening sessions however, my ears preferred the non-fatiguing smooth sound of the RedWine and its batteries. It must also be noted that the Isabella had the advantage of system synergy in an all Red Wine system, and Shindo reportedly likes to be surrounded by Shindo gear. As an aside, I've decided to try a pair of boutique NOS tubes for the Isabella as I feel that could make a better improvement on my gear after hearing some in the Shindo.
In conclusion, both pieces of gear sound exceptional to my ears, and I would love to own both. At this point, I cannot, and I had to make a decision one way or the other. At this level, I think it's definitely different strokes for different folks. I tend to listen to my rig intently during longer periods to relax. Who knows, a year from know my preferences may have changed, but for now I'm a RedWine guy.
