if you have someone local on here that has either the duetto and/or 15es and would let you play with them then that would be a safe bet so you know what you're getting and if you really want it as well (for many the stalling is a big issue). maybe someone on here will chime in and help you out. good luck...
I'd say the Duetto. First, it's a bit smaller, and very comfortable to deal with. Second, because it doesn't have as much throw (12mm vs. 15mm) it doesn't stall out near as badly when doing complex curves. It WILL still stall, but not as bad, not as easy, and not as often.
I *was* going to say Mike Phillips actually liked the Duetto over the others. (Note that isn't saying he "recommended it". Being as in a thread back in November 2013 he said that he'd stayed away from recommending one over the other (21 vs. 15 and the then new 12/Duetto). Saying basically he didn't "jump on the hype train"... but after working with the Duetto he would (not only get on the train) "volunteerr to be the Conductor of this train".
>>>
So what I wrote before was I was never on the Hype Train for the Rupes 15 and 21 polishers. I like them and I like how they work, in fact I'm amazed at how well they work considering the technique is 100% exactly opposite of everything we have all practiced all of our lives with all the other tools. <<<
>>>
You guys are going to love these two new tools. I never jumped on the hype train for the 15 and 21 after they reached the tipping point and their names and popularity went cyber-mainstream, but I'm impressed with these two new tools so much that I'll volunteer to be the Conductor of this train.<<<
In fact; THAT is the reason I bought the Duetto. Which at the time you couldn't buy by itself, instead you had to purchase the entire "kit" at $500.
Don't get me wrong, I do not regret buying the kit at all. I actually think it's a great way to go.

rops: It included the Duetto, 2 blue pads with blue coarse gel (
compound), 2 yellow pads with yellow fine gel (
polish), the foam interface pad along with 2000 & 3000 grit sanding discs, the Rupes apron (
which is a nice soft apron, and doesn't scratch your paint), 4 of the really thin edgeless microfiber towels (
not a big fan, but they are soft for a really thin, really lightweight towel) AND the Rupes bag. That bag is VERY well constructed! I think it's a better bag than the $59.99 Flex Deluxe bag (
which I also have).
The GG6 will still spin better on all surfaces than the Duetto however. Doesn't matter if it's ultra light pressure (which the Rupes machines demand) or you're bearing down and hammering through a job.
The Duetto is smoother (
vibration wise) but it's honestly
louder (with that high pitched Rupes whine). Nothing else sounds like a Rupes.
Took me another year to buy the Flex however and honestly..... even though it's heavier, it does a better job with all surfaces, with all different size pads, and with less user input, whether that's one-handed, or club-fisted.:dblthumb2:
Which is why Mikes post in this thread is a bit of a surprise. :dunno:
It's still a good idea to read up on how to best use the Rupes, no make that REQUIRED reading.
Mike's "hype train" statement is post 16 of this thread.
http://www.autogeekonline.net/forum.../72653-new-rupes-lhr75e-mini-action-sema.html
This one is also good reading.
http://www.autogeekonline.net/forum/auto-detailing-tools-accessories/72613-rupes-lhr75e-mini.html