Not used anyone on odesk before and tbh, would be hesitant to do so.
Personally, I would either use someone I actually know, or someone on boonex who I know will at least know the script.

Ive had a few custom jobs done, and each time Ive just used members here who have built the mods I needed changing.
It may be a slightly higher price than an unknown on odesk, but at least I know they will know the script to work on...

Each to their own I guess, I dont think adding the option with odesk see more is a bad thing.
I would still stick with the 'known' though and not open my site up to someone I really know nothing about on another site...