To Tame A Land
Original is one of my favorite Maiden songs. This cover is weird. LaBrie's vocals are absolutely horrible, drum sound is bad and while guitar/keyboard interplay brought something new it could've been done much better. Still it's one of their best covers... they aren't really good at them tbh.
Ronnie Rising Medley
Metallica, on the other hand, always had good covers. It's a tough job covering songs sung by Dio but James did a pretty good job although he didn't have too many hard parts in this medley. They picked best parts from each of these songs and apart from Lars they all did a pretty good job. This gets my 1st vote.
For Whom The Bell Tolls
One of the most original covers in the game IMO. Moonsorrow pretty much transformed a thrash metal anthem into a viking battle song. It isn't better than the original, but it's surely more epic. Gets my 2nd vote.
Maybe I'm A Leo
Never really rated the original, same goes for the cover.
All Along The Watchtower
Most overrated cover of all time. I just don't get it.