Personally, I prefer the 777. Since its been around for a year or two now, it's a much more mature aircraft, with a lot of great liveries for every operator imaginable. There are also some brilliant modifications - Pumper's cockpit being the pinnacle of these. As well as this, you get four models in the extended package, one of which has two engine options - a good deal of you ask me! To me, the 757 just feels a little bit incomplete - not that it isn't a good aircraft, it just hasn't yet had the time to be refined and upgraded, and while there is a steady flow of new liveries, it isn't quite up,to the point of the 777 yet. As well as this, full SID/STAR support will be a while yet, something I do miss when flying it.