Here are my thoughts on the Feeldoe. We've had ours, a Feeldoe Slim, for a number of years now and in general like it.
Some things to note: unless you have exceptional control it is not really a "harness free" dildo. We found it to be much more stable when it was in a harness, but that with that extra stability it worked great. It does provide some internal stimulation for the female wearer, and the vibes from the bullet carry nicely to the bulb end, but it only has one "on/off" setting. The Feeldoe is also not very soft as silicone toys go, still a good feel, and a nice weight for balance purposes.
We've also found the bulb to be a nice handle of sorts for solo play.
Is it worth it? I think we've probably gotten our money's worth out of it. I enjoy it, it's more interactive than your typical strapon, and it's a solid product that has lasted us over 5 years (and showing no real signs of wear).
Still I'd be curious to try something like the: Share so I had a point of comparison. The design looks a little more developed than the Feeldoe.
In either case, I think both would be probably best used with a harness. Other than that, they're not hard to use.
Boink pretty much said everything I could've said on the topic. I'd really like to try the Share at some point, because the internal part looks much easier to have a hold on. Either way, I'd recommend using it with a standard o-ring harness, just for better control. It's definitely quality, though, and it'll last for a long while.
Thank you both for your input. My partner recently came home with something similar to the feeldoe, but it is no where near as expensive, and was impossible to use for its intended purposes. Like you said, it has a nice handle!
It was fun being silly with my partner trying to get one of us to try and get it to "work" but we ended up laughing more than pleasuring each other. Oh well, lesson learned!