Blackberries, cherries, Dates, Oh My!

Any experience with using any of these fruits (and more) in a strong beer?

 

I have heard that the seeds of blackberries can add an astringent character (I don't know if this is true, but they are a PITA to filter out later). I have frozen blackberries, thawed them, and then squeezed 'em through a cheesecloth to get straight juice. I have used this (laborious) method for a couple of melomels (fruit meads). No experience with cherries.

New Glarus comes to mind (Raspberry Tart, Belgian Red). They use a considerable amount of fruit in these beers and the fruit character is very overt.

Listened to this not too long ago:
http://thebrewingnetwork.com/shows/990

 

I've used sweet dark cherries (from frozen) in secondary for a Belgian Dark Strong and it came out fantastic! The BDS has a lot of character with the cherry flavor coming out on the back end.

Just dumped them in secondary, racked on top and let it sit for about 3 weeks. I tie wrapped a hop bag doubled over around the auto siphon so I wouldn't get any fruit crap in the bottling bucket. Worked like a charm.