Many times yes. In fact the last time was only a few weekends ago, though the casks suffered somewhat from the extreme heat.
On all previous occasions it has been perfect.
The biggest difference is that it's unpasteurised and unfiltered. There's a much fuller flavour to it, a little less carbonation as you might imagine, though not as flat as British cask conditioned.
As TBN said, it tastes like normal PU* but more woody but there's a little bit more to it. It's very hard to describe without trying them side by side for yourself.
My advice, go and try it! It's something that's not easy to find, even in the Czech republic.
[size=85:2upt3i8h]*That's not a bad thing[/size:2upt3i8h]