Its a pretty popular malt, for your IPA i wouldn't use as much as 5%.
I use it at 5% in porters mainly but it is most widely known as a malt used in dark beers from belgium.
It is a lovely malt and most brewers i know would have some on them at all times.(maybe not in there pocket)
Gives a nice caramel flavour. I've mainly used it for dark belgians, but thrown some in a lot of dark beers. Tried it for a dunkel weizen, but that didn't come out the best. A little too caramel/sweet.