Not great. It's two parts are fairly thin, so it will be more prone to snapping if you forget to kick it down. If you've broken a fair share of highbacks I'd be wary. Only time will tell with these. They are comfy and very enjoyable to be in.
Go ahead, drink that kool-aid.
FS: Forum Sauce 142 $200 plus shipping
FS: Flux SE30 $75 plus shipping