Hi

First of all, Everest is notorious for massively overpricing all their product lines.

Secondly, I’m not sure what you mean by ‘a booster’. If you mean ‘voltage optimisers’ then I have written an article about these here:

PV solar panels and Solar Edge inverters

Thirdly, if you haven’t seen the ‘boost’ in output they promised, then the term ‘not fit for purpose’ springs to mind.