I have always used front carry, since I got pick-pocketed at Churchill Downs age 16. I survived in a South American pick-pocket- university town using this same system. In the US, thieves usually just hit you on the head or kill you and then take your money and stuff. I think foreign pick pockets are much better today, not sure what world work well.
Anyway, today I use something which isn't even a wallet. It's a 3"x3.5" inch heavy nylon pouch, which can hold picture ID, a few cards, my magnetic bus ward which I can just swipe in the pouch. It also has a strong nylon adjustable strap with a terminal key ring. I put my necessary keys for my apartment on this, one for the security doors, one for my unit door. I started doing this because I can wear it at the gym. A good side benefit is once I was used to the feeling of having it tucked between my belly and my belt, I am very unlikely to accidentally lock myself out of my place. Most stores with loyalty cards, even REI, library etc. will take your phone number, and my number will be stable forever. I carry junk cards like Costco etc in my backpack, since if it gets stolen it won't really matter. Backpacks are just easier-to-carry purses, thought they are vulnerable to grab and go so I never carry anything critical in them. I carry mini-umbrella, toothbrush, mouthwash, Pepto Bismol chewable, floss and some 1oz packets of almonds- just your basic urban survival kit.
The only negative I have found is that the wallet gizmo strap should be longer, so that the keys will stay securely out of sight in one's front pocket. Often, the typical stupid but violent criminal would not notice this in your pants behind your belt. I do carry $100 or so on a cheap but good money clip to have something to pay the thief to please not murder me.
I cannot remember the name, but I bought it on Amazon.
Ha