Ey! This is still my topic!
Ok, you contributed much more.  

So just to give an update, I can confirm what eurobitcoin said. I played around with "medium risk" and "aggressive" settings. With medium I had quite a few trades a day. Setting back to aggressive instantly traded all USDs to BTCs and then did nothing. Putting back to medium it sold some BTCs right away (I guess to have some USD to trade with). Looks to me like "aggressive" means that you would put more trust in the Bitcoin price raising in the future than with "medium". Right now I would recommend the medium setting. I had the robot running for about a month now, my profit was around 13%. Had I not used the robot and just placed the whole amount in BTCs (place and hold strategy), I would have had a profit of about 24%, since BTC raised from 100$ to 124$ in this past month. But this could be due to the fact that I changed the settings a couple of times. I don't recommend you do the same. So I'll be more patient this month and go with the flow.

@eurobitcoin: Looking at the custom settings, to me it looks like the robot just compares the BTC price of MtGox and BTC-E and assumes there is a time delay between the two. Since most of the trading is still happening on Gox, a significant change in price will happen there first, BTC-E will follow a bit later. Am I right? What if major trades on BTC-E influence the price on BTC-E only? What if MtGox is no longer the main exchange and Coinbase, Bitstamp etc. gain traction? Thank you for your reply. Oh, and one more thing: Is the assumption that "aggressive" gives you more profit than "medium risk" wrong?