This is the later MOLLE II version with zippered, internal sleeping bag compartment.  MOLLE I had separate, dismountable Modular Sleeping System carrier.  USMC FILBE pack is very similar.  Identical to MOLLE II packs commonly seen in the horrendous (but dye-able) UCP camo scheme.

http://www.unclesamsretailoutlet.com/SDS-Woodland-Camouflage-Large-Rucksack-p/4921.htm

Some folks prefer the later Molle II Ruck for its simplicity and some slight weight savings.  Woodland versions of these are uncommon, due to switch to ACU right about that point in time.  Woodland Sustainment Pouches available separately on same site.  

Anyways, 25% off sitewide, and free shipping through today (16 FEB).  Disclaimer: no financial interest.  

I picked up an ACU one from USRO a couple of years ago.  They're good packs.  You can put a lot of stuff in them.

The ILBE pack is fine, but was surplussed by the USMC because it didn't work well at all with body armor.  The MOLLE pack frame is designed to be GTG with body armor.

If you don't contemplate wearing body armor, the ILBE is a fine pack.

Pack arrived today, after an unusually long delay.  Appears in almost new condition, but I did notice a 5/8" slit and a 1/2" slit  on the bottom of the pack.  I'll repair them with glued internal and external patches over some stitching through pack material and inner patch.  It is the MOLLE II version, with tan QD buckles.  Identical to the latest UCP packs, except for the camo pattern.

This damage was hard to see, and possibly escaped notice of the vendor.  In any event, rather than go through the process of returning the pack, I elected to repair the slits.

Repair process is thus:

1) Sear the edges of the slits so as to prevent un-raveling of the fabric.
2) Glue a patch on the inside of the pack substantially larger than the slit.  Round off all corners to prevent the patch from pulling off at a sharp corner.
3) Stitch across the slit through both patch and original material, using good nylon thread.
4 Glue a suitable sized patch on the outside of the pack, rounding edges.  If you have enough woodland camo cloth, you can duplicate outer camo pattern, thus making patch almost invisible.
5) Rub a little glue onto the internal stitching just to prevent it from getting worn.
6) Done, and your patch will not fail, and neither will your pack
.
For those unfamiliar with the MOLLE system, the MOLLE I pack was shorter, and a Modular Sleeping System carrier was strapped onto the frame below the main pack.  The idea was that the Soldier--or Marine-- could detach the MSS carrier, and strap something else in its place if need be.  In practice, this turned out to be impractical.  So, the MOLLE II pack was born.  It's longer, and has a zippered sleeping bag compartment at the bottom of the pack.  What is interesting is that there is a zippered divider between the main body of the pack and the lower compartment.  This divider also has multiple lacing grommets, in case the zipper fails, OR to increase or decrease the volume of the lower compartment.  If one increases the volume of the lower compartment, one decreases the volume of the upper compartment, and vice versa.  This arrangement also saves a little weight and complexity.  It also allows some additional PALS webbing to be added to the sides of the MOLLE II pack, possibly enough for a pair of additional sustainment pouches, and certainly enough for smaller pouches.

Either one is GTG, if you set it up right.  Google for MOLLE instruction manuals.  The main reason for making this post is that MOLLE II packs in woodland camo are fairly uncommon (this is the only vendor of such of which I know) and the Woodland camo pattern is way better than the undyed UCP camo pattern.

MOLLE I pack image: http://ep.yimg.com/ca/I/yhst-40864295455031_2263_91353462  Image from Old Grouch, a dealer on this site.  He's GTG.

MOLLE  II pack image; looks like the pack is far from full: http://www.armyproperty.com/Resources/NSN-Listings/MOLLE-Rucksack.htm