Yeah, I feel you, mate. Master of Unblocking saved me from an Argus Agony yesterday... and also kept me from killing far too many Big Bands when I was doing Walking The Beat yesterday. That got annoying after a while.
Between Master of Unblocking's Armor-stacking and Can't Stop The Beat letting Big Band armor through projectiles while dashing (though I assume this doesn't apply to Blockbuster projectiles, since I've definitely stopped a dashing Big Band with Argus Agony before: also, can Master of Unblocking trigger from this? I feel like it should, but I dunno), Resonant Evil Big Band can be really annoying to deal with.
I concur with moisterrific, Resonant Evil is very much worth evolving to Gold (though if you get two, maybe keep one at Silver for Silver-Only/No-Gold fights).
Also, I dunno how Resonant Evil stacks up to Private Dick or Epic Sax Big Bands stat-wise after evolving to Gold, and I dunno anything about Private Dick since I don't have one, but I would assume that Epic Sax is better if you're looking for a Big Band that deals a lot of damage (his Signature ability does extra damage with every hit of a combo and also grants a random beneficial Combat Effect every 20 hits, which would be amazing if you have Specials/Blockbusters that hit a lot of times, like Beat Extend/Strike Up The Band/Tuba Tuba/others I'm forgetting about), while Resonant Evil is better if you want a Big Band that can potentially survive anything (with Master of Unblocking, you can get a potential 3/4/5-stack of Armor during a single combo, thus greatly reducing or negating all damage until it wears off, and also has a chance of Stunning enemies when he gets hit while having Armor... although, this requires getting lucky enough to trigger these effects, and that Big Band get hit in the first place).