I don't have any experience with them directly, however Aquatherm was my runner up choice before opting for TechnoSolis panels a couple of years ago, and due to the fact that Aquatherm had what I think is a better optional aluminum header clamp, I ended up using those to mount my TechnoSolis panels instead of the TechnoSolis basic U clamp. (header diameter according to the spec sheets was nearly identical between these two brands, I think about 1/20 inch difference on the 2 inch headers) One thing you should be aware of if looking at this as a DIY project is that the Aquatherm panels are also sold by Elm Distribution as a private label product (same panel, I think some differences in warranty, ...)
Ike