Fast growing doesn't mean there aren't any speedbumps - but for the most part, I've found it to be a rather smooth ride considering how much we've grown (have been with company as it grew from ~400 to over 2,000.) The challenge of the speedbumps can be part of the fun.
As for sales - we're often dealing with status quo - can be a little harder to sell into, but that changes monthly as we only continue to grow and get recognition.