Yes - we definitely learned a lot, which was helpful when we decided about six years later to get our current rental property. However, this property is located in another state (where we may move back to in the future), so we will be renting it using Airbnb.
We would use Craigslist again to sell our current home. That being said, if we were looking to do real estate investing and set up a team where we were selling our home, then I may go the realtor route. Obviously it is important to have a good sense of your market if you aren't going through a realtor before going that route.
Regarding using Craigslist to find tenants, I would as long as you have set requirements that you are using to screen by. If we were looking to scale our real estate portfolio, then we would more likely look for a property manager.
And I'm not sure that we would have kept our first house even if we hadn't had a horrible rental experience. At that time in our lives we were more focused on our careers and getting back to one house felt like a relieve! Also, I think it is harder to rent a house that you have remodeled (and not specifically with renting in mind). In our current house, we know and expect a certain level of damage but it was hard to see that in a house we had invested a lot of our time and money!