I think you misunderstood Earthling's reply; I've never found him to be given to insulting people who are simply trying to figure things out. I believe he was simply saying that there's a lot of additional information on finding the right pack on the other section of the forum.

Give it a look - you may find a lot of your questions have already been asked and answered, and you can save yourself some time by reviewing the threads there, rather than recreating them here (and waiting for answers.)

You didn't say in your original post what attracted you to the Advent. If it's on sale, and will hold all your gear, and is comfortable when loaded, go for it. However, if you're looking to invest once in a pack that will last a while, and are willing to spend a little more, you might check out some other packs. In the Gregory line, you might want to look at the G-Pack and the various Z-series packs. You might also be a good candidate for several of Granite Gear's packs, such as the Vapor Trail or Nimbus Ozone.