The best part about the SlingShot 300AW is the fact that you can easily access your equipment without taking the bag off. Since the large flap that lets you access the main compartment wraps around the side of the bag as well as the front, you can unzip the side portion while the bag is positioned in front of you and safely pull out your camera, lens, or accessory flash. A pair of clips keeps the front portion of the flap from opening accidentally and spilling your gear. An added bonus is that you can rest your elbows on the side of then bag when it is in front of you, thereby adding a touch of stability to your camera in situations where a tripod or monopod might not be practical. A small pouch on the inside of the flap can hold up to eight compact-flash cards or some batteries--or some of both--and closes up with Velcro to keep those items secure. A small, microfiber cloth is built in to the main compartment to cover your camera's LCD screen and keep it from being scratched when you open and close the bag. Another small mesh pouch is mounted just below the microfiber cloth, so you can toss in other odds and ends.
If you take the bag off completely and open the flap entirely, you can quickly reach every part of the main compartment, for quick packing and unpacking. The bag comes with an ample supply of pads inside, which can be configured as needed using the strips of Velcro on their sides and edges. It's not quite as versatile as the system used by Kata, in which all the material covering the pads is Velcro, but I didn't have any problem building a configuration that was very useful for my shoots. I was able to tote Canon's 1D Mark III, with the company's EF 70-200mm f/4L IS USM attached, along with four other smaller lenses and two flash units. Given the layout of the interior, only two of those extra lenses were really easily accessible. To get to the other two, I had to unclip one of the safety clips and unzip the side a little more, being careful to zip it back up and clip it again when I was done. Still, the SlingShot 300AW provided one of the best on-the-fly lens-changing experiences of the many bags I've used.
On the outside of the main compartment flap, there is a small front compartment that can hold business cards and pens along with a cell phone or iPod. Unfortunately, it would probably be inconvenient to carry your cell phone in that compartment, since you'd have to shift the bag from your back to your front anytime the phone rang. I would have preferred for Lowepro to include a cell phone attachment for the strap, though that is uncommon on a bag of this caliber. Lowepro does offer a wide variety of add-on pouches, however, so if you want to add on, there is a spot on the strap for one of those optional pouches. A larger compartment comprises the top of the bag and can hold larger items, such as battery chargers, memory card readers, or a small umbrella or light jacket. It also has two mesh pockets, one of which closes with a Velcro cover, to wrangle other smaller items. The one thing the top compartment doesn't have is a pass-through for a set of headphones, so if you plan on listening to a music player while it's in the top compartment, you'll have to snake the cord out of the zipper, which is a less-than-perfect solution.
With this bag fully loaded, you can easily end up with a very heavy load on your back. The strap is well-padded, however, and there is also a padded waist belt that does an effective job of keeping the pack over your center of gravity. In fact, it ends up transferring a lot of the pack's weight to your hips. Of course, you have to take the waist belt off if you want to bring the bag around front, but the belt is very nice to have in other instances. Another nice feature, which Lowepro includes on a lot of its bags, is the built-in rain cover. A Velcro-sealable pocket in the bottom of the back of the bag provides a home to the cover, which is made of ripstop nylon and could potentially save your equipment if you get stuck in a sudden downpour.
My biggest complaint about the SlingShot 300AW is simply that it is a sling bag, and since I often end up wearing a camera bag with a dress shirt (with buttons all the way up the front), I am not a fan of the fact that all sling bags end up putting undue stress on my shirts' buttons. Putting that slightly unfair criticism aside, the Lowepro SlingShot 300AW is a great bag for anyone in the market for a sling-type camera bag. Its innovative design gives you easy access to everything you need while shooting, while providing a good amount of storage for ancillary items. Plus, as usual, Lowepro includes top-notch construction on the SlingShot, a bag that should last a long time.