I have the Kick Medic, I got it for Christmas and haven't used it since. The cord gets in the way of your kicking motion and it's impossible to get a natural shot off with it. Plus, after you kick is, you have to reel the cord in, so it's a complete rip off really.
I'd advise getting a rebounder if not an actual goal. I have a homeade 8x24 goal that I made from PVC pipe, the pipe cost about $150, the net was about $40(but you can get a cheaper one) and my dad & I made it in a few hours
I also got the Star Kick for Christmas
(I made my mom take it back haha). It seems like it doesn't do sh*t for you. Kick a ball at a wall instead of getting one of those, it'll bo you more good in the long run and it's way more natural.
So in conclusion, both of those are rip offs. Get a rebounder or a goal of some sort intead of wating your money on one of those.