JLG Crawler-lift: Ditching ladders and scaffolds for "high inside" work

Finished training last week on how to operate a scissor-lift, and during a break, the instructor showed me a compact, crawler-mounted boomlift marketed by JLG. Here's a photo of it inching through a doorway (twentywheels.com):

I haven't used it, but the idea is cool enough - a track-mounted machine that:

• Fits through a 40-inch-wide doorway;
• Can crawl up a 40 percent slope;
• Expands its footprint via hydraulically actuated outriggers; 
• Is powered by rechargeable batteries, needing no IC engine or power cord inside;
• Has a railed platform at the end of an extendable boom that, in the largest model, would let me change a light bulb 75 feet off the floor; and,
• So I hear, costs a quarter-million dollars.

Photo from JLG of the big one in action:

And, for the well-heeled handyman, it would be very nice for roof work (photo, twentywheels.com)