This is my very first review on Joomla Extensions Directory. I have registered on JED especially to review this extension. I have tested all extensions on Site Performance category, but Jbetolo performed the best for me. It has all the features to boost the speed of a Joomla site. It can merge, minify and compress all JS and CSS files in a single file. And have lots of other options to control the behaviour of the extension. I can't stop myself to recommend this extension to everyone. You can check the difference by using YSlow. It has boosted my YSlow points from 56 to 87. Support from Gobezu(Author) via email is also very superb. So, give it is try guys. You will surely thanks me :) and Gobezu.