Sling Bag Upgrade

So after trying to fit my insulin kit, iPad and wallet in my small sling bag, I've decided to get something more suitable. Ideally, I want to get a sling bag suitable for holding an iPad, insulin kit, wallet and leatherman. Additionally, I would want have room for my DSLR (with an attached lens), an additional lens and one spare battery.

So far my research has yielded the  following three;

http://www.kata-bags.com/3n1-11-for-dslr-w-mid-range-zoom-lens-1-2-lenses-flash

The Kata 3N1-11 has the option of being left or right sling, as well as a backpack and its "X Position" (where the backpack straps cross across the chest). The DSLR compartment is very flexible in its configuration, and can be accessed from both sides. Reviews say that the laptop slot will technically fit an iPad, but that it is very snug. The top compartment is apparently roomy, but I think I would have trouble fitting anything other than my insulin kit.

http://goincase.com/products/detail/dslr-sling-pack-cl58058
The Incase DSLR Sling Pack is exactly what it says on the tin. A sling pack for DSLRs. And an iPad or Macbook Air. Only having a right hand sling does seem like a limitation at first, but it does mean the construction would be more solidly built around not having to support inverting it.

http://www.crumpler.com/AU/Camera-Bags/Camera-Backpacks/Enthusiast.html

With the Enthusiast, it feels like Crumpler built an amazing shoulder strap design, then attached a bag to it. The strap can also be reversed for left or right sholder mounting. The DSLR compartment is very simular to the Kata in its layout and ambidextrous access options.

At the moment, I'm leaning towards either the Incase or the Crumpler, motivated mostly by the thicker shoulder strap. But the Kata does have a more versatile set of strap configuration options.