Hey, I've got one of those. and got it for a specific purpose. My normal daysack is a Berghaus Munro which is great and will just about do for an overnight trip with tarp instead of tent. I've got a much bigger Karrimor backpack for mutli day trips. The Rocket Pack, well I got it for my attemtps at widlife photography when I want to spend a few days in my local wilderness, ie large forestry plantations. At about 60 litres in total so it's plenty big enough. SInce it's a military inspired design then it's can be used whilst wearing "belt order", ie carrying stuff on a waist belt. So the substantial belt on the Rocket Pack actually goes round your waist rather than on your hips like a traditional trekking pack, I like to carry my camera gear in belt pouches which is just about imnpossible with a traditional trekking pack..

So... Pluses: It's robust, and roomy
The side pockets can be ziped off, and used as a day pack if you buy an additional yoke.
The olive green colour and camo rain cover are great when I'm out trying to photograph deer

The cons, it's military looking, especially if you use the rain cover!
The belt is quite high up, more waist belt than hip belt, which might not be so effective if carrying heavy loads for long distances/times, but I haven't tested it to that extent yet.
You have to buy an additional yoke to carry the pockets as a day sack.

Justin