Hi mplkw,
You’ve probably read this already but there is more about the pros and cons of the different types of mattress protectors and also some examples of each of them in post #89 here.
I don’t know the more detailed specifics of each of them (such as the specific knit or the weight or thickness of the fabrics they use) so the most reliable source of this type of more detailed information about each of them would be a phone conversation with a knowledgeable retailer or manufacturer that sells them that can provide you with the more detailed specs and information about their protectors and help you compare them to other similar protectors that they are familiar with.
There are some comments from Cheryl at Cozy Pure about their protector in post #12 here and some feedback about them from forum members here and here and here and here and here.
There are some comments about the Vasilo protector in posts #24 and #26 here and here a forum search on Vasilo (you can just click the link) will also bring up more comments about it as well (and other similar protectors).
There are some comments about the Suite Sleep protector here and in posts #17 - #20 here
There are some comments about the Berkeley Ergonomics/European Sleep Designs protector here
I don’t know of any feedback on the forum from anyone that has purchased the Sleeptek protector.
Hopefully any of the forum members that have purchased or compared any of the stretch knit protectors you are interested in will also see your post and share their comments about the ones they are familiar with.
Phoenix