We were recommended WarmUp loose wire system for our wet room and it's been brilliant, it's been in 4 years now. I didn't look at alternatives though and just went with what my builder recommended. We've got porcelain tiles over the top and it is lovely
I've never heard of Prowarm or Warmup. The only two different systems I know are electric (dry) or water systems (wet). We have dry and I absolutely love love love it. It is so different to radiators as the whole room has a comfortable ambient temperature. However, it is not cheap. The first year we had it, we just had it on loads. Then we got our electricity bill . Now I regulate it a bit more.