does anyone have any experience with this website and/or product?
No experience, but it sounds interesting so I did a little research. Basically, it is a condom catheter shaped to look like a natural foreskin to cover the glans. You can buy condom catheters for under under $2 each on Amazon and they would perform the same function. For that matter, you could cut the tip off an ordinary condom and wear that all day if you could figure out a way to keep it from falling off your flaccid penis. Condom catheters tend to fall off and I doubt SenSlip stays on any better than the best condom catheters or medical manufacturers would have adopted the superior technology. I would recommend buying a couple of condom catheter tips and experimenting with those before shelling out big bucks for something like SenSlip just for the aesthetics.
If you were to gain sensitivity to any noticeable degree by keeping your glans covered, you would have to continue to wear the covering indefinitely or the sensitivity would be quickly lost.
There is no way to restore the millions of nerve endings removed when the exquisitely sensitive foreskin is removed during circumcision. That skin and those nerves are gone forever. Wearing protection for the nerves on the glans cannot restore sensitivity to the equivalent of an uncircumcised penis. It is important to understand this.
Male circumcision is just as barbaric as female circumcision and for the same reasons, but male circumcision is somehow acceptable, normal, preferable, and even celebrated in the same places where female circumcision is illegal.