Adriaan,

I'm rather surprised at the blow-out to ten minutes for that basic shred-the-tokenised-string-to-a-table approach.  I've done this several times as a way of dealing with SSRS multi-select, and found it fine for performance (although really it's a bit crude and hack-y).

Was there anything obvious in the  query plan (of the porly performing query) to indicate why this was such a bad thing to do?