Anybody who can play a standard harp and sing at the same time is good from my perspective. When they can get (and hold) my attention singing a lengthy song in “olde English” some of which is a little baffling to me, then they are really special.
“The Lady of Shalott” has undergone a number of changes over its considerable lifespan, but I believe Tennyson (the apparent original author) would be very happy to hear Loreena McKennitt’s take on his poem.