I have have had a Papaya mother for three years now and, while I have had strains better in some ways than she is, I have yet to find a plant that I feel is better than she is. I have grown strains out in selections from Mr. Nice, Big Buddha (Cheesus is a great plant), Green House, Barney's, DNA Genetics, Seedsman (horrible in all my experiences), Positronics and Joint Doctor's (just to see), as well as other strains from Nirvana, and so far Papaya is the only mother I have kept.
In my experience Papaya takes its time rooting, but seems to always come through at the end. I have never had my clones root in less than two weeks, and, when cloned right and treated well, I have had near 100% success rates. I once had a batch of clones in my room get to 104 degrees (air conditioner went out) and wilt almost completely over, all I did when I found them was cool the room down and mist them with ro water, and I still had 100% of them root, the only consequence was that two had burnt from the heat so badly that no viable nodes were left.