Hmm...that's a tough question. If you go and look at the pictures here
, you can get a good idea of the layout of the bag. The sleeve for the laptop has about 1/4" of padding all the way around, and as you'll see in the pictures, the laptop kind of sits in the middle of the bag. The back pocket that you see would take the brunt of the damage if you dropped it on that side. The sides are also reinforced slightly. All this said, I really don't know how it would hold up to abuse. The bag is definitely well made, but it's also very slim in design. I don't think I'd recommend the bag if you're one of those rough-and-tumble types, but for most people that take reasonable care of their gear, I believe it would be fine.
If I had to choose a rating based on your system, I'd probably say somewhere in the 5-6 range. This is said having not owned or ever seen a Haliburton case though, so take that with a grain of salt. Booq offers a 30 day return policy, so all you would be out would be shipping costs if it wasn't durable enough for your needs.
Sorry I can't be more helpful, but if you'd like to see some specific pictures, I can do my best to accomodate you this evening when I get home from work.