I got a real Dremel, and I bought it at a discount... So if you haven't got the Dremel yet, be on the lookout for a company to buy a cheap batch and put them for sale cheaply, or price reductions because the 2013 model is coming just to name a few examples
As for the actual tools... I suggest you stay with the Dremel ones. You'll be guaranteed they actually fit: I bought a Proxxon tool a while back and the shaft has too small a diameter for my Dremel with the current 'mounting head' (or whatever you want to call it). Also, you'll know for sure the quality is good. After all, of most tools, how often would you need to replace it? The tools that were supplied with my Dremel 2 years back are still in good condition, and I use them regularly.