I ordered a pair as well. Jim explained the S3E offers about 7hz lower in bass extension vs. the other S3 models (but otherwise is similar). I imagine the upgraded mid will provide 'more' detail in contrast. The cabinet dimensions are obviously different (specs indicate 2.5" deeper & 2" wider & 2" shorter than the S3, S3A, S3AT model). There are some YT vids of the entry level S3s @
https://youtu.be/sELMuXF4OvI. I realize you really can't draw any conclusions without hearing a speaker in your home...but Salk makes a very good product at a reasonable price. The custom crafted cabinet work alone exceeds what can be had comparatively speaking.
I've had the WOW1 (exchanged them for the Salk Silk monitor). I loved the Salk Silk monitors...just decided to go with a tower (personal consideration & preference). I sold the Silk monitors to purchase the S3E (very easy to do btw---so that's another indicator of a great product). Beyond the excellent & meticulous build...the Salk brand sounds amazing...neutral yet lively. IMHO as close to live music as you'll get from a speaker. I also love the fact that Salks don't add or subtract anything from the recording. It's just as advertised (neutral).
I'm sure there are 'better' speakers but I'm convinced that 'difference' heard would likely be negligible or simply preferable to another listener. The S3s have received very favorable responses so I trust they'll deliver. Jim doesn't strike me as someone that would release any speaker design if it wasn't good to go. He's seems restless when it comes to quality (whole team...Dennis Murphy).