Personally I find most of the aforementioned ticklers to be average. Each and every one of them goes for the standard techniques, on the standard spots, no imagination, exploration, mapping the Lee, it creativity whatsoever. Not to mention that digging painfully hard in the ribs or armpits, or scrubbing the soles with a hairbrush, many times elicit crazy reactions because they're just very aggressive techniques that make us feel uncomfortable. Good lers don't just go for the most brutal or harder technique, they study their Lee and adjust to their weaknesses.
Having said that, I quite like the amateur ticklers of the multiple Brazilian studios, the girls of UK tickling, Pandora from bound to tickle (or something like that), and probably many others whose names I fail to recall.