There are a couple things I'd like to weigh in on with regards to this discussion. First, there is a BIG difference between the Purity (or any of the "Design" line) and the ESL line speakers. Although the Purity is a nice speaker, it's not a Vista or Vantage. You will find the soundstage is a LOT bigger (wider, deeper, AND higher) with the ESL-series speakers. Second, depending on the amplifier you are using, you will also find that the mids are a lot more fluid and natural and the bass is a lot more tight and realistic with the ESL series.
I think the Vista gets short-changed by a lot of people because of how they hear it. Many dealers view the Vista as the "budget" speaker in the ESL line, and therefore set it up with low-powered amps or even receivers, but they have the Vantage (and of course the Summit) powered with top-notch amps and components.
I've heard the Vista driven by proper amplifiers (Krell, Bryston, Sunfire, and ARC) and actually I think they can be, with the right amp/cable combination, on some music, better in the bass range than the Vantage. The main selling point for the Vantage and the Summit are that they have powered woofers--personally I think this is a weakness. The Vista is a passive speaker--it has no on-board amps, and it is bi-amp-able, so you can hook proper amplifiers to the woofer posts and they actually DO something. When you bi-amp the Vantage or Summit, the on-board circuitry takes that speaker-level power and turns it to line-level, then amplifies it with the on-board amp, so no matter WHAT amplifier you are using with a Vantage or Summit, the woofer is ALWAYS going to be really driven by the on-board amp. Some folks mat find this is a good thing--ESPECIALLY is SAF is a big issue, or they are at a premium for rack space for amplifiers, but personally, the way I see it is that if someone has enough balls to buy speakers that cost $7k-$10k, they should have enough balls to over-ride any SAF-related objections to a stack of proper amplifiers in your system.
Anyway, I think in many ways the Vista is actually a better deal than the Vantage, for the very reason that it DOES NOT have on-board amps--it is more versatile, and can be more easily tailored to your own listening habits and bass demands, ESPECIALLY if you like your low-end a little on the "punchy" side. The Vantage is a "smoother" speaker than the Vista, but I think that with the proper amplifiers, the Vista can actually be a real sleeper. You just need to throw a LOT of current at it, like a Sunfire or Sanders amp.
All that said, I STILL think that the new Martin Logan ESLs don't throw the same expansive soundstage as the older models, ESPECIALLY when it comes to the height of the sound. Sliding the panel down to be less than 60" high seems to REALLY have really sacrificed a lot of soundstage height, all for a tiny increase in SAF. Sure the new ML's look a LOT more cool than the older models--slimmer and a lot more sexy, but I still think that the Summit sounds a LOT smaller than the Prodigy, and sounds practically TINY compared to well-tset-up Monoliths or Statements...
I'm sure there will be a LOT of people on here that disagree with me on this, but this is what my ears have told me, based on listening to a LOT of different systems with a lot of different music.
