Wow. Thanks for sharing your detailed review. These things make sense now...I reached out to the only UK-based customer who was on the "Wall of Wins"/ review page...it turns out she is one of the 6 profiles who come up on the blog/ "community". When I checked her LinkedIn profile, she did respond to Sara (the main contact for signing up) had been very useful. I headed over to her Medium profile - she had loads on there, but one single follower and absolutely 0 claps on any of her content.
I suggested she might want to use publications to reach an audience; her response was that medium was just a way to build up a portfolio...Her work on Contena is published on other sites, though.
In any case, I think I'll pass! Thanks again!