As the former Tri-anim Rep for SW Texas, I sold a LOT of the MedSource bags. I also used this particular bag as my demo bag for about 4 years, which was stuffed and carried into every account I visited and so did my husband, the Tri-anim SE Texas Rep. We used one for our trail ride first aid bag, and I have one of the MedSource coated canvas large trauma bags for my equine first aid kit. The guys that run the company guarantee the bags and if you ever have problems, you simply send in the broken one and they will fix or replace it at no cost to you, except maybe shipping. They usually just replace them. MedSource is a GREAT company with nice products at reasonable prices. (By the way, I NEVER had one come back in for repair)
The 4 inches can really help when you are trying to stuff a couple of c-collars in the bag. The back outside pocket (the side you don't see in the picture) runs pretty much the full length of the bag, so works well for collars and flat-style head immobilizers. The front two pockets are great for glucometers and bandaging stuff like 4 x 4's, tape, ABD pads, etc. The dividers on the inside attach with velcro so you can change the dimensions of the compartments, or you can remove them all together. Besides, we all know that the bigger the bag, the more stuff we will jam into it... 4 more inches equals more stuff!
I don't know much about LA Gear, although I had a couple of customers that had them and loved them, too.
Good luck with your purchase! Oh, and for the record, I am not in sales anymore so I have no vested interest in what bag you choose, I am just very familiar with the MedSource one and really like them.
Christine Springfield