I never did find anyone who had used the Mast Lift, so I bit the bullet and bought one. We used it for the first time today and it worked as advertised.
Pros: It works as advertised - hoisting effort is considerably less than the physcial effort of using the ATN Top Climber. Simple for one person to use, although for safety
purposes I prefer having a second person on deck
Cons: A tad heavy to hoist the winch
drum to the masthead, but managable. Each pull on the hoist line only raises you around 10-12", so it takes a while to get up to the masthead. Arms got a bit tired in the process but you can always stop to rest. When you begin descent, there is an initial 2" or so sudden drop while the internal brake disengages - not bad once you're used to it, but unsettling when you're not.
Cost of course is a major factor - this may be a more viable purchase
for a yacht or sailing club or group, or marina, than for an individual. The total package (drum, endless line, bosun's chair) is bulky and heavy and could present a storage
Bottom line: On first blush, I'm pretty happy with it. I'll be using the system later this year to paint
our masts (the main reason I bought it) and I'm pretty confident it'll perform in that project