I stumbled upon UShip while googling for a moving company. I had a great experience using Uship. All I had to do was provide an approximate inventory list and I got 4-5 quotes. Almost all were cheaper than the regular moving companies quote. Before booking I was able to confirm that the quote provided would be binding and the movers that I booked (MR SURPLUS) did a good job loading and unloading my stuff. I think I saved around $500.
For each quote I could see reviews from users that had used the moving service before. That helped a great deal in making the final decision.
Although I didn't try, I am assuming I can use the service to move single furniture item. Before when I didn't know about UShip, I had to move a couch from a shop to my apartment, and the service provided by the shop was quite expensive. I am quite sure that had I used Uship then, I would have found a suitable mover at a reasonable price.
Since I don't have experience regarding "big" moves, I can't comment on that. But I would definitely recommend using the site for small moves (1 BR or less).