We bought similar window perches (similar to the linked ones above) many years ago. We never had luck with velcro versions, but the screw-in versions held up relatively well. The cats loved them, although the fabric sagged over time due to their weight. Eventually we made our own perch for the cats. We used a piece of laminate MDF as the base, put a 3-inch lip around 3 sides of it (stained to match existing woodwork), and then mounted it to the wall right below the window using decorative shelf brackets. We then put just a regular cat bed on it; the lip prevented the bed from sliding off. Since we mounted it to studs and/or used wall anchors, it was super sturdy. So...if you're handy, it's another option to consider, although jumping up might still be a problem.