I recommend Share vs Feeldoe. It doesn't fall out as easy (I could never get the Feeldoe to stay in very well without a harness). I ended up giving my Feeldoe away to a friend. I really love my Share though, I like having the added stimulation while wearing it (and it is also useable with a harness).
Honestly...I will never buy a feeldoe. I bought a share. They are amazing...and the bulb that goes inside is bigger and more snug for a better grip. The share has the different sizes. It can be used with a harness such as a O-ring...but I would suggest using it with a boxer/rodeOH strap.