I’m a 6 foot with long arms (+4″!) and the large running a 50mm stem and 750mm wide bars.
The top tube is relatively short on paper but the steep seat tube pushes the reach out so it feels longer when stood.
It is perfect for me for everything from big trail rides, tight techy stuff to DH tracks. Any shorter and I’d be too cramped.
Just over 33″ inside leg and I’ve got about 25mm spare drop on the Reverb, so that’s worth bearing in mind.
(edit – similar comments to above, too slow typing, watchin Josh and Danny at Windham WC! A med would definitely be too small for me though, so you are right on the borderline.)