Hi
I have 4.0 and 6.2 oxygen had them about 1 year and think thay are grate.Had no problems well built very stable handles gusts well nice smooth lift when the wind picks up.And very fast on speed runs very good kites in my opinion.
I'v owend a libre special for about 2 years and youse it on the beach most weekends and not had any problems.The powder coat will chip but the steel is galvanised so no rust:) I allso use it for free style and find it ok for ground base tricks and have maniged some small jumps in it not shore if it will take a hard landing.