I am currently working on a Riolis kit myself and I will be very glad when it's finished! The wool does make a nice effect but you have to have loads of patience to work with it! Its harder to thread (get a larger eyed needle!) because of the wool fuzziness, if the kit calls for blending the strands are extremely fragile so you have to use much shorter strands and the darned wool has a tendency to catch on any rough skin or fingernail. I can't count how many times I've yanked the floss out of the needle while stitching and so had to re-thread.
So far it looks like this company provides OODLES of the required fibers though so there's no shortage at least on this kit. I did try to convert the colors to DMC using the color chart but some shades are just so darned close!
This kits are doable but only if you have the patience and time to work them. They're worth it even though personally I don't want to try another one! ;)
Oh and this is entirely my own personal opinion!