I have only played with it for an hour or so, but it works! It's in a funny menu location, so it feels like an afterthought. The implementation is a littly klunky, but the screens are well done (setting key ranges, etc). One thing I did notice was that you can only have 128 multisamples (total per "project")...that may be a deal breaker for some.
I did quick multisamples of Mellotron violins and choir and they came out great (once I got the interface figured out).
Just my $.02.
Roland Fantom G6 (2), G7, VK-8M
Korg M50, CX3