My first board was a used piece of junk off Craigslist and it was perfect for the first year I was learning, then I moved on to a off the rack longboard, which I've had for four years.
This spring I knew I wanted to try something different, but I didn't have a clue what that would be, so I opted to get a custom. I really enjoyed being able to talk with a shaper and get his help to figure out what kind of board I would get the most enjoyment from....and when I did finally get the board a few weeks ago it was worth the wait, it was exactly the kind of shape I wanted, but I doubt I would've had much luck finding such a good match from an off the rack selection.
And the price of getting the custom was good, darn close to what I would've spent to just get a crappy GSI, so I figured why not?