My wife is an ICU nurse and main hunting partner is a Firefighter/Paramedic so I've had some good guidance on picking the right kit. Most of the time when I'm in the field I have 1 of two setups with me:
The kit from Gundog Outdoors, yes it's marketed as a hunting dog kit, but it's better than the majority of "human" kits out there and the owner of the company is a retired firefighter paramedic who specifically put it together to serve both roles. It's legit. It's also heavy. Add a high quality tourniquet and stapler and you're ready for all but the most gruesome backcountry situations. One of those items that I hope to never use, and cuss about how much room it takes up, but could literally save multiple lives.
For smaller trips my wife sends me off with the larger of the HART kits that you can buy from REI, slap a tourniquet in and you're pretty well set.