I’ve done the Swadesh list lexicostatistics: 89 of 100 core words, which is comparable to Russian and Ukrainian. (I get the same figure for Cypriot.) Mutually intelligible, but just. Much more now that the dialect is dying out.
I was exposed to the dialect 30 years ago when it wasn’t doing as badly; so I’m not necessarily the right person to ask; I’d be interested in others’ opinion.