I think it sounds decent for a Bluetooth headset. I haven't heard a lot of BT headsets so take that for what it's worth. I have noticed the sound signature is definitely different wired vs bluetooth. I am honestly surprised so many audiophiles have said otherwise. I feel like the bass is a little sloppier and almost overdone while running on BT. I also think that makes the recessed mids a little more noticeable as we'll while on BT mode. Honestly I don't really notice though unless I A/B it to wired mode. I feel like this headphone is very similar to the m-100 when wired. The bass doesn't extend as low but it has not been an issue for me. I use the XL pads so that increases the bass overall anyways and may be why I notice more bass when running on BT.
I wouldn't really consider myself an audiophile, I like bass and I like a headphone that sounds good. I'm not looking for something that is going to be completely neutral. That being said I do producer/audio design work as a hobby so I do appreciate a nice sounding headphone that has detail and I feel the CFE deliver detail but they are definitely a V shape sound headphone. If I am mixing/mastering I wouldn't use this headphone. I would use this as a headphone while on the go, at work, gaming, etc.
I like the CFW and find them enjoyable and will be keeping mine. I like the features of the headphone and find it fun to listen to... Even in BT mode. Is it the best BT headphone? Probably not. Comparing to other headphones in this price range (sub $300) I feel like it is a worthy contender. Sure you could spend more and get something better.. There is always something better.