We used it to move cross country ~5 years ago. It was great, would recommend.
Some caveats:
1) You have to arrange pickup/dropoff to and from the train station on either end. We got our parents to help on one end; if you're moving at the same time as your stuff, you can do it yourself.
2) Make sure you follow all their rules for packing the boxes. There's a limit of 50 lb per box, and our parents ended up re-packing some large boxes of books at the train station to stay under the limits.
Otherwise, it's probably the cheapest way there is to move cross-country. I bet it's more reliable than your average moving company, too.