The most important thing about machmetric is that it gives me an idea with how my site performs or not in terms to load time, performance etc which helps us improve our sites as well. It's really easy for user friendly interface too! I don't have any problem regarding using this tool from its features are very good so far but there may be some minor issues like sometimes when i open multiple windows at once then only one opens up instead rest remain closed? This can happen if you use Firefox browser also please make sure what version do u r running because recently they released new update (v2) where now we cant see all tabs opened together anymore unless their size less than 5mb each!! So try out latest v3 otherwise keep waiting till next release. If anyone has no issue related loading times just go ahead by downloading free trial first before buying anything.