Instead of focusing on the pack itself, I hope you have done a good bit of backpacking and can focus a bit more on weight. /u/joelicious5000 makes the fantastic point about fit. FIND A GOOD FIT. After that is preference. I've had both, and I like internal frames. Organization can be an issue, but it is easy to work around.
Weight! Shed it as best you can. I don't use a pack cover; I use a trash compactor bag in the main compartment and a turkey baster bag inside my compression sack for the sleeping bag.
Shed weight in areas such as...
Flashlights: carry a pair of Photon II microlights rather than a traditional flaslight.
Knife: Swiss Army makes a VERY small knife that also has scissors (people might laugh at it, but it does most any job you might need on the trail).
Water Purification: the Sawyer is fantastic, and grab three 32oz bags (and then carry 1 traditional bottle, or use the sawyer inline with something like a camelback). It is light, works great, and takes up very little space (when you don't need to carry the extra water).
Insect Repellant: 100% deet, 1 (or 2) oz bottle.
Ground Pad: Foam Pads such as the RidgeRest SOlite is fantastic for the price. If you really have trouble with just that, then Thermarest makes the Prolite Plus.
Treking Poles: I use a pair from Costco.com. yeah it is 'more weight', but it really sucks hard to hit the ground. Gotta get used to them, and they aren't for everyone.
Sleeping Bag: Kelty Cosmic bag is more than sufficient for the trip.
There are lots of places to shave down weight, but there are a few things that I will take that I could do without: iPod(type device) with a number of audiobooks and podcasts. And a way to recharge it long enough to get through the trip (this could be an external battery if it is just me, or add a solar panel for the group to share).
Also, you can wrap your water bottle with 10' of Duct tape, add a patch of tape that holds 3 sewing needles, and now your dental floss (be sure you can thread it) is also your sewing kit. The duct tap is fantastic for patching tents, shoes, whatever.
There are lots of places to save weight and still have prepared gear. Feel free to ask qestions!