Ok you asked for it.
So rather than give you answers, I'm offering questions. Sorry.
What's your budget?
Is the ST standard as much as you want to spend?
What is upstream from the speakers?
Source, pre-amp, amp, integrated, receiver?
How particular are you about sound?
The ST's are radically different from Magnepans as are most cone driver-based speakers.
How did you like the Paradigms?
They're nice speakers.
In all honesty I've never heard the STs. I own HT-2s.
D'Appolitos are very dynamic and the STs have the addition of a TL cabinet for better bass response.
If at all possible, listen to some more speakers and really define what is important to you.
Your open-ended compare question is a tough one.
I view sound systems as just that, systems.
It can be hard to isolate one component's quality without taking the rest of the system into consideration.
I believe Salk has a 30 day return policy, order up and see how you like them in your home.
A lot people are not comfortable with this arrangement but it really makes a lot of sense.