Alright, this may be a dumb question but...
How well can this pack be compressed down for short day hikes?

I was considering the Manta series (also has the mesh suspended back) but they lack any tool attachments. Stratos series has 1 tool attachment that looks pretty small and not very useful. This pack might be overkill but if it compresses really tightly and carries well with minimal gear in the pack, I might bite the bullet and get this instead.

I can pack a full weeks worth of gear in the atmos and be a little over 35lbs...I like the numbers for the the granite gear, except where you say it can only carry 30lbs. for some people thats hard to achieve even for just a weekend pack...

My husband and I just got back from a day hike and I carried the Atmos 50. You can cinch it down to fit your load and it carries well.

Ya, I basically just discovered the discontinued Osprey Atmos 35 the other day and wish there was a current option just like it. I like the ability of it to carry heavier loads, the double gear loops, the more durable materials, and yet the continued use of the mesh airstream back of the Atmos. I feel like I would be compromising and being forced into buying a lesser quality pack if I purchased a Manta or Stratos series pack. If others agree that using an Atmos 50 for a day hike doesn't seem like complete overkill and the pack can be super-tightened down for minimal gear, I may choose this over the Manta 30 or Stratos 36. I am definitely hoping to hear more response to this thread though. Thanks! (And thanks for the recommendation of Granite Gear but I really enjoy the "trampoline" suspension offered by Osprey).

Hey there, The size will depend on what you are carrying,but you can totally cinch down the Atmos 50. The comfort is awesome and it has no durability issues. I wouldn't consider the Granite Gear pack that Jason lists above, unless you would like to go ultralight. And in THAT event, go with the Exos 46 by Osprey. The other thing to always consider is the warranty by the vendor. Osprey has an "All Mighty Guarantee" that they stand by 100%. Your fault, Osprey's fault or the "bear's" fault, Osprey will repair or REPLACE your pack for any reason. That is my kind of warranty!

I have a smaller backpack but I use my Atmos 50 most of the time for short day hikes. I can carry what I want for day trips and it is a very comfortable pack. My back stays dry because of the mesh back panel.

Although the Osprey Atmos Series of packs are good, I would encourage you to check out the Granite Gear Vapor Day Pack. It's lighter, more comfortable, and more durable than the Osprey. Lighter, because it doesn't have the complicated frame of the Osprey. More comfortable because of the 2 layers of foam in the backpanel, wastebelt, and shoulder straps (vs. the die-cut, single layer foam of the Atmos), and more durable based on the stretch woven (think Schoeller Dynamic) material on the backpanel (vs. mesh on the back of the Osprey), 100% Cordura branded materials used (Osprey uses a variety of materials not all of which are made from Cordura threads), and very good construction (Osprey does a great job at this as well). The Granite Gear Vapor Day Pack is arguably the best day pack available. It can carry up to 30lbs comfortable and weighs in at 2lb 2oz. (full lb. lighter than the Atmos 50). It's also $50 less! Check it out here: http://www.granitegearstore.com/Vapor-Day-P115C29.aspx.