You are describing a Pal Mickey. Yes, I've tried it. I was able to use one for one day for free as a DVC member. I had the option of purchasing it, which I chose not to do.
For an adult with no children, Pal Mickey became more of a nuisance than a pleasure. It is unweildly to use the clip that affixes itself to your clothing or backpack strap. You need to hold it quite close to your ear to hear it in the parks or when in a group of more than a few people.
If it does not synchronize properly when entering the park, it will not provide timely or accurate information. The one I had didn't synch properly at the MK. It told me about the afternoon parade (The parade is about to begin in 15 minues) after I had left the park and returned to the room! Also, it didn't have much information to share in the MK.
I didn't have that problem in the other parks, just the MK. I did take it to each park for the day I had it to see the differences between the four.
It needs to be protected from becoming wet. Hello? Florida? Summer? Rain! Pal Mickey had to be stuffed into a waterproof bag and into a backpack during the rain. Not much use there.
I thought the jokes were cute, although more than a little corny and the games were ok, but boring after a short time.
All in all, I didn't find it useful or fun enough to purchase.
I'd recommend renting one and using it before you decide.