Hi,
here are my experiences with the activator:
Finally got myself some custom made fake braces from bracesshop.de (activator with tongue crib and pelottes). Thanks to the buccal tubes, they can be worn with a headgear, too (cervical, high pull or combination headgear). I prefer the combination headgear - wearing the braces with it makes them feel like a custom gag being forced into your mouth. My mouth itself is pretty filled up with smooth plastic and a lot of wires, the tongue crib restricts the tongue movement hardly and the pelottes keep the lips away from the teeth. The palatal arch is the only wire your tongue can freely play with (besides the tongue crib wire). It offers many interesting sensations to feel.
I can speak with the devices on, but it's a little bit unclear/I have slight lisp.
Hope this helps. Feel free to ask questions if you want to know anything more.
Kind regards