It depends on what you understand by "guile". I interpret as an intelligent ability to understand the batsmen's weaknesses and try to fool them with your variations of pace, trajectory and spin. Despite his limitations, I agree that Giles had plenty of that and I have seen him get some good wickets with it (for example, the manner in which he drew Sehwag into a false stroke & bowled him in the 2002 Natwest Final). Vettori has more talent and guile than Giles; Panesar is undoubtedly talented as a spinner, but so far he strikes me more as an instinctive bowler in the Harbhajan Singh mould than a thinking one. Look at the Indian; a few years ago, he used to bamboozle international batsmen and I still recall Gower and other commentators swearing blind to a golden future. He is still a good bowler, but there are distinct sign that oppositin batsmen have learned to read the signals correctly. I feel that the same thing might happen to Panesar over passing years; time will tell.