It's very versatile despite the fact that you wont use the bag combo as much, it replaces the should strap, thus you need to take it off before you're able to open your bag.
The size is perfect for me, roomy and still small enough not to slow you down. I even use it as waist bag when I shoot. Did you try google for a review?
I use this bag. The top half is too small to hold anything useful, though I have used it to carry a water bottle and a towel for short hikes sometimes. The bottom half is big enough to hold my d30+grip + attached midrange zoom, as well as 2 other lenses (1 telephoto and 1 short prime), and a flash unit. The compartments are self-adjustable, so you can configure the interior to your preference and liking. The AW cover is very useful for protecting the bag on rainy days, and tucks away nicely in front when not in use. There is also a top slide-in compartment which is very convenient for carrying my passport and documents (folded) when travelling.
My only gripe is that the zip on beltpack is on the side of your body (to prevent theft I suppose). I have trouble opening the zip easily and quickly while shouldering the bag, and usually have to put the beltpack down on the ground to take things out and put things in, so that slow me down quite a bit.
This bag is spacious and ease to configure interior compartments. The bag also distributes weight nicely over hip and shoulder in backpack configuration, well all to your hip.
If you dont like waistbelt, Orion AW isn't for you. Although you can just use shoulder straps for carrying it in backpack configuration, I find that two clip-on connectors are too flimsy for holding the weight of beltpack to daypack. I find that you have to use both shoulder straps and waistbelt for it to be secured.
Beltpack is 7in deep, making it protruding a bit from your waist. This makes beltpack very combersome in crowded places as you will constantly bump into people. Beltpack has center of gravity too far outward from your body to be comfortable as beltpack only configuration.
I find myself just using the beltpack as shoulder bag most of time, but find that shoulder strap is not too comfortable for long haul.
I am actually looking into Mini Trekker to replace my Orion AW.
