Hi, Brian I have both the 757, and 767 and they are both remarkable aircraft. The 757 has a few issues such as the rocking back and forth as DAL191 mentioned. From my experience the 757 doesn't really rock but it has before. Sometimes the ILS system is a little buggy but not usually. The 757 takes a bit of a hit on frames but it's nothing that will make you stop flying. I run FSX on a laptop and I really don't notice anything more than a few frames. As for the 767, I haven't noticed any big bugs no rocking, and no ILS issues. People seem to say that the 767 takes a very big hit on frames, and that was something that made me a little skeptical about purchasing the 767 because I run FSX on a laptop. I was pleasantly surprised to find that it is not nearly as bad as I had expected not any more FPS loss than the 757. From my findings, the 767 has more features than the 757. The most obvious being the more detailed and complete virtual cabin. But maybe when Captain Sim updates the 757 which will be this year, it may include a full cabin with more detail. As for expansion packs, the 757 includes the 757-300 and 757F. The 767 includes the 767-200, 767F, KC-767, and E-767. It's hard to say which one to get, because they are both great aircraft. It really comes down to what you are looking for and what you are going to be doing with the aircraft. No matter what you choose, you will probably really enjoy it! Happy flying!