Late to the thread, but count me in the "Pro Foam Cannon" camp (with caveats).
I've only made it as far as the Griot's Foaming Surface Wash (the mild white stuff), which I'm sure is much milder than the Built Hamburger (

), but it absolutely makes a difference when it comes to washing a legit dirty car.
Example: Did a wash this morning on my road warrior (80mile/day commuter), it's been 2 months/ about 4000 miles of MN Winter driving since it's last wash (Don't judge!).
Pulled the car in to the shop, foamed with Surface Wash.
While it was dwelling, hit the wheels with Surface Prep diluted down in a trigger spray bottle; then used boars hair brush w/ car wash soap to clean wheels.
Pressure wash rinsed, followed with single bucket/single mitt wash.
Despite being trashed to start, I wasn't getting huge grime transfer on my mitt as I went. The wash bucket now that it's settled barely looks darker than when I started.
Nothing fancy for LSP; got Griot's Ceramic 3&1 in July (no polish beforehand). No drying aids, though I did play around on the hood/roof with some different combos, but no discernible difference in dirt accumulation/washing.
I will say (I think each time this topic comes up), I've never been a believer in using a foam cannon with regular car wash soap prior to doing a contact wash (IE: Snow foam car, proceed to bucket wash); to me I find it hard to believe the standard soap bubbles add that much lubrication to the process.
Bill's Extreme wash method with a foam gun absolutely does make sense for someone looking for extreme lubrication and safety.
Bilt Hamber and the other touchless options are definitely appealing; I'm just working through my current inventory before I'm letting myself accumulate more.