Back to the OP. The Auto-Trim tuners appeal strongly to my geek/hacker side, but I still prefer to use a pair of side-nipper pliers to cut wire. My cutters get trued up once in a while, & tossed for scrap when they stop working; in a tuner, it just seems like one more thing to wear out, especially with stainless-steel strings.
I get sorta the same feelings about the Steinie heads. I've always liked the unique look of the reverse Firebird, with them gold banjo tuners. And the Steinies just look so cool, period. But I figure you'll lose a LOT of convenience.
(1) when you load a string, you're apparently supposed to pull the string tight while you crank down the setscrew, & a few reviewers recommend pliers-tight.
(2) for me, even 18:1 is overkill; I grew up learning on friction-peg instruments, so I find 12:1 a blessing! If the nut & bridge are good (lubed, no sharp edges), I can restring a guitar in near-darkness in less than 15 minutes without breaking a sweat -- that 40:1 means I'd at least have to buy a crank for my cordless drill.
(3) and because of the 12:1 ratio, when I switch between regular tuning & drop-D, it's one fast twist & a brief tweak, almost as fast as a
Scruggs peg (look it up). If you use multiple tunings during a set, & don't want to swap guitars, that could be some LONG moments with everyone staring expectantly at you twisting wildly away.
(4) the string end apparently has to be cut close to the post or the end will dangle out, kinda spoiling the look.
(5) there are some good cases out there that won't have clearance for the back of those tuners.
IN SUM: if they're worth the hassle to ya, then they're worth it, right? They're super-accurate, very stable, look cool, & don't cost a month's pay.
FWIW, here's the current instruction set, & a legacy version:
http://www.steinberger.com/media/StnbrgrGrlsTnrInstruc.pdf
http://www.steinberger.com/images/gearlessuse.pdf
On acoustics, the "snob appeal" tuners are Waverly. Individual 16:1 open-gear machines, $150+/set.