WL Mail is fine. I'm just an old geek trying to figure things out. I don't like the fact that WL talks to servers as regularly as it does (twice a day), but I think this is just a hang-over from their transition date - at least I hope it is. The only other thing I would guess is that MS is moving to the cloud computing model and that means clients have to check in with servers. As I said, I'm an old geek - been there done that.... centralized computing, decentralized computing, time-sharing..... same thing different name
You'll have to play around a little to find where they stuffed options, configuration and what-not. That's the price we pay for progress. It's a fair price, methinks.
The GUID folders created in AppData\Local cause no problems - they just bug me. They belong in either the app's folder or in a temp folder. But they pose no threat and they don't consume resources - well a little - they do exist, but they're empty.
So, go ahead - bite the bullet and go with Live Mail. It does have some neat features, and it has that damn ribbon that I really don't like. But then so do many other "modern" applications. I did pretty much the same as you. Didn't like it, re-instated WinMail, and then reinstalled Live Mail.
Dag nab it - that's progress for ya.