I've bought hundreds of books from Colin. What i will say is this:
Extremly nice, honest, humble and friendly. Lacks a sense of humor but no one is perfect
VERY tight grader. Not a single book over graded, either bang on or even under graded.
VERY helpful. Since i like in the UK he would let me ship many of my books to his house and ship them all to me at once. Who else would do that for a stranger? Well Joeypost does too
Price wise he was always willing to negotiate, never looking to make insane amounts of money. Very patient with payment a couple of times when i needed an extra week or so to get the money.
One of the nicest people i never met and the best thing to come out of Alaska since Sarah Palin