Hey i wrote the review for the big red one. It does not get a lot of use, partially because my wife has a nerve condition in her stomach now, and partially because it seems like we prefer super size with plain old dildos instead of strap ons.
I have tried multiple girth and length extenders to please my little size queen and most fall short. The big trouble is finding one that fits your manhood just right. My wife loves huge (think BAM, Rambone, Holmes, and Stryker). But I am also well endowed (8 Inch length, 5.5 around) so I might try the 8" version of the toy you posted about.
I like this because it's silicone and can be sterilized for pegging. i would just fill it with a glass dildo for pegging.
What are you going for? Something to wear over your manhood, something to just use as a strap on, or something to peg with?