ML Aerius or SL3's?

SL3 no question about.

I have the SL3's and bought them at the time because the larger stat gave more of the ML sound, and I like the better bass extension. I agree that it is, all other things being equal, superior. However, if you have a small space and value cohesion between the stat and woofer, then the Aerius is worth considering. Either will sound good with okay electronics, and great with great electronics. Whichever you get, drive it with the best you can and you will be well rewarded. I just came back from CES and many of the systems on display there couldn't hold a candle to my humble setup. (of course, there were more than a handful that really were very special, too!)

I owned SL3's for nine years....tube amplification won't cut it...you need a ss high current amp with at least 200 watts at four ohms and 400 at 2 ohms...these are power hungry designs.
Larry

SL3 no questions about this!! I own a pair of SL3 for almost 9 years and I still don't have an upgrade itch yet without paying big bucks for replacement such as B&W 801D, Wilson Watt, Sound Labs M1 and etc. I use AR VT100 MK3 to drive them and am very satisfied with the sound. Go with SL3 and you won't regret it. The only problem is that the panel will sag and you need to install a stopper to keep the panels up (check out the ML user web site and there are solutions to address this problem).

I can add to the chorus suggesting the SL3s are better than the Aerius. I will, however, add a slightly dissenting comment to Larryken's. High-powered (Larryken was right in that they need lots of power) tubes with the SL3s are so much nicer than "regular" SS that I can strongly recommend them. I also think MOSFET amps sound great with Martin Logans.

I found that SL3s were more enjoyable to listen to - larger listening area, better all-around bass, and for me the Aerius seemed "tinny" where the SL3s sounded "fuller." For me, the Aerius is the Martin Logan equivalent of bookshelf speakers - and when one considers them that way, they are probably among the best deals in used audio.

I have heard the SL3s (I used to own them) with my VTL 450s, with a big ARC, with a lower-powered Pathos hybrid, a RedRose hybrid, with Counterpoint NPM monos, with an Innersound amp, and with a variety of SS amps. My favorites were the VTLs, the Counterpoints, and the Innersound. I could not buy the Counterpoints (already sold - though my dealer let me listen anyway) - it would have been a toss-up between them and the VTLs. The Innersound was also quite nice. The key to all of them is the ability to go down to about 1 ohm (at the highest frequencies) without "complaining." I think I read somewhere - I believe written by a tube amp designer - that the "ability" for some SS amps to 'double down' into lower ohms was the reason why Martin Logans sounded better with tubes.

I put them away years ago and finally sold them about a year ago. When I brought them back out and set them up so a friend could listen to them, I was pleasantly surprised about how good they sounded. They do not go ALL the way down in the bass, and putting them too close to the back wall to get some bass reinforcement can be a recipe for disaster.

One more idea, contrary to your request (though I did put my specific opinion above): IF you can deal with the size, I personally would instead recommend a pair of Martin Logan CLS speakers, on good VERY solid stands (which will give the CLSs considerable "oomph" in the bass for some reason), and a very good subwoofer (the classic pairing is the Entec though I have not heard that particular combo). I think CLS + subwoofer is absolutely sublime, and also very good with high-powered tube amps with low minimum output impedance.