I've used the Silhouette for many fabric cuts and it's been great. Once in a while a little piece won't have cut all the way through, but I don't mind that since I despise cutting it all by hand.
That's not to say there isn't work involved, but it has been superbly useful for me. I recently quilted a US flag and cut all 50 stars with the Silhouette and it was great. There's no way I would have ever done that by hand. I've also cut designs for other themed-wall hangings and it was great. I asked if there was a difference at all between the fabric blade and the paper blade with the machine and it's just a different color casing so that you can keep them separate. I'm not really bothered by that answer but at the same time I guess I was hoping for something more. It's great for cutting EPP papers.
I separate the blades I use for fabric and paper, and I always apply my heat transfer first.
I like it for cutting strips and squares out of fabric. It does speed up the cutting process but it is an investment. You also have to be okay with a little bit of waste. You can minimize that by folding your fabric but you will still get more waste than you would with a regular rotary cutter and ruler.