hmm. you just reminded me of something that i read in my junior high school (for 13 year olds) days... if you get 1 liter's of marbles, and 1 liter's worth of marbles (or 1/2" steel bearings if you don't call them marbles in your country)... and mix both portions into a large container, you would not get 2 liters' volume worth of the mixture. kind of like trying to dissolve a large amount of sugar or salt into water - you just get a marginal increment in the volume taken up. i think there's a concept called "granularity" ( http://en.wikipedia.org/wiki/Granularity ) which might apply to our discussion. the salt and water could represent all the random sized items we're cramming into a pannier...

while this analogy seems bad (i know, it's me...) consider the likelihood of using a pannier like lonepeaks (i use ortlieb backrollers, FYI...) it should take somewhat lesser volume to cram in multiple small ziploc bags into an ortlieb rather than fit a single package into a zip compartment and waste the extra space.

while i am starting to use my ortlieb backroller for my daily work commute WITHOUT my bike for waterproofing - i sure can't imagine getting a lone peak and NOT being able to guarantee my things will be bone dry - and fitting in my 12" sized work laptop. i belong to the category of people who would love to get things that are truly multipurpose - although i'd appreciate further organization abilities within my pannier - but hey, that depends on the programming that i have inside my head, wouldn't it? one more thing i like is that i can hitch up one of my ortlieb panniers as a backpack for sightseeing while guaranteeing that everything inside's all dry while i can't really imagine doing it with a lonepeak - not sure if that option even exists or not.

another caveat i might foresee is that in a zip-compartment scenario (no, i've never inspected nor studied a lonepeak before) is that there might be scenarios where the more fragile items have to be packed somewhere near the bottom of the entire pannier - all it takes is for me to be slightly forgetful before i squish the item(s) into a mess of goo.

p.s. i'm currently a B&B type of tourer, so please do take my points into your context

one more thing - i'm not sure if lonepeaks will allow you to add additional pannier hooks on top - i just added one more pair of clips to both my ortlieb backrollers so that:
1) the load is more spread out across 4 points instead of 2;
2) i don't need to constantly shift the hooks' position using allen keys when i'm using my ortlieb pannier carrying system (backpack adapter)
3) there's always some form of redundency in case any one snaps
4) anyone (airport crew, porters, myself?) lifting a heavy pannier by two sets of loops that attach to the clip releases will spread out the stress of the lifting over 4 points instead of 2...

one last thing - i will never need to face the hassle of cleaning off road dirt from between zipper safter a wet ride, as compared to rolltops, nor have the need to further add the cost for a set of rain covers to the purchase price of the lonepeaks by themselves. smooth fabrics (i chose the ortlieb classic PVC - i'm not a PVC fan but neither am i an anti-PVC activist) are much easier to wipe clean instead of cordura-like fabrics.