The cooked beef is usually served with roasted potatos and a mixture of fine cutted bread dumplings with horseradish and small apple pieces.
My personal opinion about Tafelspitz? It has a very big name in Austria, but I am not that excited about it. The taste is quite boring. No spice and no exciting flavour. It's not bad to eat but I would never again order a Tafelspitz in a restaurant.
The price? Rather expensive. Tafelspitz is usually one of the most expensive dishes on a menu. This Tafelspitz on the photo took almost 12 Euro. Wiener schnitzel and roast pork are always much cheaper. But it's an important part of the Austrian cuisine. At least I have tasted it one time.