If so, how was it and do you see it being the future? I personally never have, but then again I don't live in a major city.
I have used AirBnb and a few others that may not qualify as a shared economy, but as a shared contribution : crowd-sourced projects, and crowd-funded projects (à la KickStarter), things like Couch Surfing as well.
I believe these will take ever more place in the future, but I don't believe they will take over the world economy to completely replace traditional economy. They will only complete it to make a new form of concurrence and help balance quality of service and prices, so traditional companies will hesitate to charge too much for a product or service that can be obtained easily in a shared economy market.
Also, these will be much more easy to create with the advent of decentralized autonomous organization that will allow all of that, but without the burden of an intermediary (like Uber and AirBnb themselves, the provider and customer will be able to interact directly). The first examples of such organisations are all the cryptocurrencies (like Bitcoin).
I use Lyft all the time, because it's cheaper than a taxi and faster than taking multiple buses.
Ever have any bad experiences?
Used AirBNB once. It was nothing special and quite pricey, although better and more value than a hotel.
Personally, I haven't but then again none of these services are available where I live yet.