No first hand experience, I've heard nothing but good things from Serious Seeds. A friend of mine did AK-47 in his guerrilla grow last year and they turned out well. I've actually been looking to pick up Chronic for several months now, but it's been out of stock. I'm looking to try some indoor and I I read Chronic is easy on the nose, so I want ot give it a run.
Side note, Serious Seeds has recently acquired Magus Genetics. I did a single Magus Motavation I picked up as a freebie from Attitude like a year ago and it was excellent. Good to hear it isn't going to die out.