NOTE: Amazon has combined reviews for the 102, 202, and 302 together. Be sure you know which review you are reading. This review is for the 102 AW.
I am a Lowepro fanatic. Every bag I own is Lowepro except for one multi-purpose Tenba Messenger bag (which is incredible by the way). I own the X300, a couple of Stealth reporters, the Slingshot 202 AW and the 302 AW. I shoot with a Nikon D300s w/MB-D10 (battery pack), Giottos quick release tripod plate, all Nikon lenses, and ALWAYS carry at least two speedlights(SB-900 or up to 3 SB-700's) w/ diffusers and small light modifiers (such as Lumiquest's line), and a heavy assortment of other gear. I needed a smaller bag to carry a minimum amount of gear mainly on family outings. Of course, a minimum amount of gear is subjective to each photographer. This bag severely (emphasis added) limits what I can carry.
The bag is constructed in the usual Lowepro high quality and high design standards. The only issue I have is that it is just too small. By the product images, you would not suspect it of being so small. Imagine my surprise when I realized it barely fit my D300s with an attached Nikon 17-55. THAT'S IT for the main compartment! To fit it, I had to remove the supplied configuration (all the padding) and put the camera in sideways. Even then, the top of the camera does not really fit, I had to stretch the bag as I closed the zippers. There is no more room in the main compartment for another lens or flash. End of story. The inside lid of the main compartment, the 102 has two Velcro-closure memory card pockets, so you can leave your memory card wallet at home. The Lowepro microfiber cloth was moved from previous models to the left of the compartment, which is kind of nice since it always got in the way with other models. Also, this version, like previous versions, includes the built in rain cover.
The secondary compartment (top of bag) can hold either a small lens, flash, or an assortment of small gear (cables, etc). But, it cannot hold all three or even two of those items. In my case, I use it to hold one SB-700 flash and diffuser and that barely fits. Inside that compartment is a smaller pocket for miscellaneous items that functions well. In my case, it holds spare AA batteries. On the outside of the bag, you have a smaller vertical zipper pouch at the top replaces Slip Lock Attachment loop) that would be another great place for batteries or your keys. But, the SlipLock Attachment Loop that used to be there on previous models is now gone. The addition of a tripod buckle, cinch strap, and hideaway foldout tripod feet pouch on the side of the 102 is a nice feature improvement. On previous models, you had 3 SlipLock Attachment Loops, 2 on the back and 1 on the side, that you could use to try to carry gear such as a tripod or monopod. The design feature improves carrying such a device compared to previous model's, but the size of the bag makes it impractical to attach anything but a low-end consumer grade tripod.
A lot of reviewers have complained about the fit of the Slingshot series, especially on women and big men. They are entirely correct. The Slingshot strap rides across the front of your chest. Women with large breasts may simply not like this feature. Larger men may have a problem as well. You can carry the bag slung over the right or left shoulder for comparatively shorter periods of time (compared to slinging it over your back). But that defeats the purpose.
In short, if you are use a pro-level DSLR with attached grip, you will just be able to use this bag- barely. Forget about carrying a Nikon 70-200 2.8 though. I barely got my 17-55 to fit. This bag is a minimalist bag at most. This bag proves the point there is no such thing as a photographer using one bag. Bag's serve specific purposes and require compromise to achieve the best form and function for any given environment. On the other hand, for those carrying smaller DSLR bodies with no grips, such as the Rebel line, or Nikon's consumer line (think D90, D7000), and have very little lighting requirements (not carrying flashes), this bag is a home run. So, all you mom's on the sideline during Johnny's soccer game could very well fall in love with this bag. Pro's, definitely not except under minimalist standards. For point and shoot camera's, this bag is overkill unless you are looking to carry other items as well; I would just get a backpack at that point.