Alchemy 31-50 took under 2 days, and total game time of about 8 hours last weekend. Getting to 26 in version 1.0 took me about 2 months of very hard work.
I too stuck with my old character but to be honest it has only helped me in that I had a few 100k gil to start off with so I didn't need to work quite so hard to buy all my gathering gear to level fisher up.
Old Nick Sargantanas
Merlon Wytarensyn - not there yet but probably Balmung