The simple answer, David, is that I don't know. The only Maggie I have ever heard is the 1.7 - and then only briefly playing Bob Marley's Exodus and a couple of other tracks. Maggies are very thin on the ground in the UK. Too be honest, for the money, I thought it was good. When I touched it, I couldn't believe how flimsy it was. Like, where are the magnets? Really didn't appear to have many, and those that where in it obviously weigh very little.
Is the 1.7 as good as a Duetta Sig? No where near, IMHO. It doesn't have the bass extension or scale.
With regards to resolution, my thoughts on that one are mixed.
I recently changed from KLM2 to KLM5 mid range/tweeter ribbons on the Duetta, as Graz seemed convinced they were better. I also had the resistors changed from Caddocks to a resistor pack that I am unable to reveal the nature of as I told Graz I wouldn't do so.
After this change, they just sounded plain odd, IMHO. Some really strange colourations appeared in the upper mid. They also sounded too sibilant. After about 200 hours of use, the colouration in the upper mid went away totally.
As I posted on another forum, after 200 hours, I believe the "apparent" resolution was beyond any ESL I have heard. It was simply astounding. But I started to suspect that this was partially a symptom of an altered frequency response. My belief was they had become too bright in the upper registers.
So I started taking frequency response plots and recording letter 'S' using my Rowland Edirol to see where the problem frequency area was. I plotted the letter S as a timed-based FFT. 4KHz to 12KHz with the problem later part of the S in the upper half of that range. Analysing the in-room frequency response to look for a problem, I have to admit I coudn't really identify anything obvious.
I decided I wanted the top end rolled of, though. Whether that made the frequency response uneven, I simply didn't care. The sibilant region was driving me nuts - too much emphasis.
So I got the refurbisher to come down and have a play, after many discussions on the phone. We tried a new inductor in the x-over, and it sounded just plain terrible. It lasted about 1 minute before with both agreed it was worse. We then tried a thicker gauge inductor. Instant success! Much improved in the sibilant region. This inductor had the same inductance value, but was thicker gauge. It is measurably different in terms of resistance to the thinner gauge wire. That it could make such a difference literally blew my mind. It is interesting to note that the prefered inductor is an original Apogee one - the only component in the x-over to be one.
The overall effect of the changes is a Duetta with greater resolution that the previous KLM2 ribbons, and also a speaker with better dispersion characteristics. I don't know why the later is true - but visibly much more of the ribbon appears to move when compared to the KLM2, and it doesn't curl as much when driven at high levels.
Post inductor change, the frequency response does not looked rolled off - they are essentially pretty flat.
If you were to ask me overall whether a Summit X has more resolution over the entire frequency range I would say definately not in the bass. I don't think I have heard better bass from any speaker. In the mid and treble, I would say the "apparent" resolution of the Duetta is at least the Summits equal, but it can "sound" higher resolution when the subjective frequency response errs on the bright side.
That said, Duetta mid/top sounds different to ESL mid/top. To my mind, it is more real and true to life than an ML panel, and produces tones like bells and chimes with astonishing clarity that is exceedingly close to reality. But there is something that the ML panels have that is very enticing, at least to these ears. I would possibly hand ML the award for handling female vocals. They're just so good at it, particularly when driven by some nice Audio Research kit.
But there is an additional complication. Just what is a Duetta Sig in the year 2010? Mine are customised and most that have been restored have differing specs in terms of ribbons and x-overs. Most that have been done have used components in price territories that Apogee would not have been able to consider.
From testaments, Rich Murray (stateside) is producing Duettas with specs that are causing their owners to be literally astonished. You'll have to pay more for the best he can do, but what better recommendation than that? Then there is Graz's Synergy, which I believe will be better still. Run them with a 20 Watt tube amp with no power issues. Maybe the best results live outside of the commercial framework, where profiteering is not so high on the agenda, and the pursuit of the best sonic results is the main consideration.
I regard my Duettas as a serious hobbyist loudspeaker, and one that I can make alerations to in order to achieve a performance level I am genuinely happy with. Good stuff, I reckon.