The Silicone Slims G-Teaser doesn't provide much direct g-spot stimulation, but has good intensity vibrations and is waterproof. It is a decent product, and would be a simple and fun addition to any beginner's collection.
The most helpful critical review
All buck, no bang
I was able to achieve an orgasm if I lay on my stomach and thrust my hips against this wee little toy, but it seems like an awful lot of effort for something with batteries.