Now they have the larger version on clearance.

http://www.sixmoondesigns.com/packs/F65_CU.html

Wow, if only I knew... Judging by volume of main compartment of 3000 cu in, accordingly to Ray Jardine recommendations, 65L is close enough to be optimal year-round for any AT/PCT/etc through-hiker and with aluminum stay it is even more capable of carrying weight than his frameless pack.

But I'd stick with mine. First, because I measured mine and all the gear I usually want to take with me on a weekend trip fits into it comfortably. I did winter backpacking even with a smaller pack, and I should be just fine. Extra volume invites extra weight.

Second, because I cannot exchange it anyway And in the long run, I plan to pack lighter and smaller, not heavier and bulkier.

Yet, for anyone who is thinking about buying one, either would be a great pack, but bigger might be better. Or not? Depending on how you think about it.

that's tempting. As I said in a previous post, I have a REI Flash 62 from 2014 that I've been using. It did well enough on the JMT carrying a BV 500 cannister and other stuff, but I was with my partner and we divvied up gear. On a solo trip, though, I felt kind of uncomfortable using it. I know, I know, I really ought to be more ultra-light than I am. I'm trying to improve my ways! Anyhow, reviews I read said it does well carrying a bigger load for those times when it's necessary (like with bear cans, solo, which I do). Besides the price seems good and it's a lighter pack than the 62.
What pack do some of y'all use? Anyone like this model? Fusion 50 does sound good, but I'm just not sure I'm really going to fit in it well enough.

The story continues:

I contacted Six Moon Designs and asked for exchange of Fusion 50L for Fusion 65L... They agreed and asked to ship the bag only (without the stay and the belt). So I learned how to disassemble the whole bag, and in a few days we shall see if I could reassemble it back without having some spare parts missing or extra.

I plan to take my "final" backpacking gear setup on an easy camping this saturday, with lightweight MonsterFly tarp, ultra-light hammock (if it arrives), new Gossamer Gear Hammock Pad (extra-wide), and Lighter1 Bear canister.

If you're considering this pack and you have a torso over 20" or so, make sure the pack is returnable if it doesn't fit you.

I really wanted to like the 2014 Fusion 65, but it just isn't tall enough for my torso. I've enjoy using it with lighter loads, but if I need to transfer the weight to my hips, I am unable to adjust it correctly.