"Poor retention system" explanation: the velcro is mismatched. There is a far longer piece of "hook" vs "loop" so that the elastic that makes contact with the "hook" is constantly being degraded. I am already having to replace both upper straps on my shin sleeves. In doing so, I will match the amount of velcro so that this does not happen again. Also, the quality of the elastic originally used, is far from up to the task...made all the worse by the constant contact with, then removal from the hook portion of the velcro.
Yes, I would recommend this to a friend, but with the warning I give above that they will have to make the same modifications that I will make.