They're interesting folks, and not just for the desire to speak an artificial language. Esperanto has a utopian ideal behind it which means that Esperantists are very welcoming, voluble, engaged sorts of people. Languages like Tolkien's Elvish may be very beautiful and artistic, and languages like Klingon may have strong ties to fiction, but with Esperanto there's a strong community of people with actual goals. It's a weird phenomenon. No other conlang has ever been quite so successful, and believe me there have been a lot of them. What's more interesting, though, is that they've created a new cultural context. It may have started from nothing, but there's now a huge amount of original music and literature in Esperanto. I'm not here to evangelize for it, but I am definitely excited by its achievements. As you pointed out, I just wish there were more people I could speak it with. I'm more than a little rusty.