Looking through the list of suspect exit nodes, they fall into three categories:
1) very low-bandwidth Window Vista systems running 0.2.4.21
2) recently dead/offline
3) one massive Linux exit
The (1) exits might be hacked Windows systems, perhaps part of a botnet --no contact given. Seems an easy call to mark them BAD.
The (2)s are probably offline (1)s and so deserve to be marked BAD as they may return.
The highly-ranked (3) with 20MB/sec is only three months old and does not provide contact information, resides in the Ukraine. Also an easy call if you ask me: BAD EXIT.