I figured this would be a fun subject to stir up and see where it leads. I've heard of a few people on the AT with its abundance of water, using a Burn for their thru hike. For most that seems a bit crazy, but it shows with careful packing and gear selection that it can be done. So let's say for the discussions sake you were going to chose one of these packs for 3-5 day trips all the way to a lightweight summer thru hike with decent water sources. They are all very similar but completely different.
Golite Jam 35 - Weight: 1lb 11oz Volume: 2135 in3, 35 LMaximum Recommended Load: 30 lbs
MLD Burn - Weight:12oz
• Total Maximum Volume: 1950ci main pack / 2200ci using extension collar
• Minimum Volume: 1200ci with compression bungees engaged.
• Main Pack: 1500ci
• Main Outside Pocket: 200ci
• Side Pockets: 150ci + 150ci
• Extension Collar: 300ci
• Pack Fabric: Dyneema X (TM)
• Extension Collar: 70D Silicone Coated Ripstop Nylon
GG Kumo Superlight - Weight: Large: 14.65 oz
Capacity - 2,200 c.i. (36 l.) total1,700 c.i. (28 l.) in main pack body/extension collar500 c.i. (8 l.) in main pocket25 lb. maximum carry capacity, but 20 lbs. is better.