I was going to answer about a friend of mine who is nearly finished with the process, but you asked if anyone reading had actually done it
My friend has been here a bit over two years as a permatourist and began to worry about being able to leave and come back as things were heating up and this was about 4-5 months ago that he started the process. He had no possibility of temporary or permanent residency.
He hired a lawyer (Gabriel Celano, who was my lawyer, and for other guys I know, for permanent residency and has been referred many times here as well) to take him through the process. It has gone well for him up to this point. I.e., no complications.
I am to be one of his witnesses as to where he lives, how long he's been here, what he does for a living, etc. He is due to see the judge (although I understand the judge himself will not actually preside, but rather an assistant) for his interview this week (although the date may change).
According to Gabriel, he expects everything to go fine, with no complications. My friend speaks good enough Spanish to get by in general queries and conversations, though he's not fluent. I'll let you know how things go when he has his interview and there's more information.
Steve did post at some point that his case was successful, and that he was taking out an ad in the paper (I'm pretty sure it was Steve who had posted that) announcing his citizenship. Someone else fairly recently posted something about that, too, I believe I remember.
I was talking to Gabriel the other day (we still keep in touch on occasion) and he mentioned that they have had to start turning away people who are applying for citizenship as permatourists. He is cutting off at 5 requests per day because it's all his office can handle. I'm not sure if he actually handles every case that comes to him (25 per week seems a bit much) but is probably handling the ones he's pretty sure will go through with minimal problems.