Good Morning, all!
I'm three weeks or so into head shaving! I'm a longtime DE/SE/Shavette/DEvette cart user who took a long sabbatical from RAD with a 7-year beard. I've been a 0-guard Wahl shaver up top, but finally took the plunge with a Mach3 with custom handle given to me by my dad almost a decade ago. I told him, "I don't need this, I'm a DE shaver!" Little did I know that my preference for a quick morning head shave would be with carts. Since then, my RAD has been reactivated with (in order):
Mach 3 with custom handle (all my old Gillette Sensor/Sensor Excel/Mach3 Red and Blue handles are MIA)
Head Blade Moto Fire Dept and Police Dept with HB4 and Dorco Pace 4's
Feather F3 Neo
Dorco Pace 4 (not compatible with HB4 and old Pace 4's)
Mach 3 with Bollin Webb R1 Handle
Mach 3 with Triumph & Disaster (incoming)
Dorco 3D Motion (incoming, I like the added pivoting of the Moto and Feather F3 Neo
Moto Sport (found a great starter bundle that I bought for the HB3/HB3 adapters)
Other Razors from my collection that I've used for head shaving:
Eversharp Hydro Magic (whoa, very nice, but a little harrowing)
I've got an extensive collection for face shaving, but this is for heads.
Cheers, I found this site from a Badger & Blade link detailing cartridge compatibility with Head Blade.