For reference, the 5.11.24 pack is "Total Capacity - 2275 cubic inch / 37 liter[/url], and MSRP is $130, except for multicam, which is $170.

THE Pack from Spec-Ops is a little bigger at 2550 C.I., but is a little more expensive, at $198 for all colors.  The yellow interior is surprisingly effective at helping one find stuff in low-light.  Construction and materials are GTG, in my opinion.

In considering any pack of this type/size, the addition of a frame sheet is a necessity, IMHO, as it gives much increased comfort to the user, and allows more weight to be carried comfortably than without such a frame sheet.  Spec-Ops offers such a frame sheet, as well as other useful accessories.  Since packs of this type generally do not have a load-bearing waist belt, the quality of the shoulder straps, and their padding, assumes increased importance, since the shoulder straps (and your shoulders) will be taking all the weight.

Be advised that Spec-Ops has sales quite often, so if you can wait, sign up for their e-mail alerts..

Other than that, a Medium Molle Ruck (USGI), in easily dyed ACU/ABU camo pattern would be a relative bargain,  It has an unobtrusive external frame, and a load-bearing waist belt.  It's considerably larger than the 5.11/S-O packs, and carries up to 60 lbs, due to the frame and load-bearing waist belt.  Generally $65-$85.