The Satisfyer Endless Love is a cute (and fun) toy that really encourages partnered and self exploration. The shape is so different than "standard" sex toys, and it doesn't really fit into any category all that well. It's too loose to be a cock ring, and it won't really stay in place looped around dildos either unless it's held in place.
I found that the Endless Love didn't really "unseat" any of my favorite vibrators, but I don't really think it was meant to. Instead, I was really surprised to find that my partner and I have spent multiple sex sessions just exploring with the Endless Love.
It's less like a "Hey, this is a great g-spot toy, let's make you squirt!" toy and more like a "Hey, this thing is kinda neat. Let's see what ways we can make it orgasmic."
And that's where the Endless Love excels. It seems to really make you (or you and your partner) sit and think about the different ways to use it - and it really adds more communication to the bedroom (I found out that he really isn't into things I thought he was - even after five years of being together.)
Plus, in the end, as a vibrator, it's also pleasurable - and can be used alongside other types of stimulation (sex, handjobs, etc) for some bonus pleasure however you plan to use it.