Hisham makes a very valid point guys, it all depends on ones level of experience and even confidence, and also to what degree someone wants to use their time.
While scratch building is one of my strengths, even I don't normally venture far off my experiencal knowledge base that is limited to a few areas where I am confident of my skill level because I have accomplished it in the past, eventually.
Time is often the most important quantity in any build? And some people value their time at a higher value than the upfront cost of an aftermarket kit or accessory package. Many of us, myself included often weigh the time commitment more heavily than the other factors when making a decision on what to build or how to build it.
I personally got into scratch building because it was cheaper than buying the kits but now buy the kit sometimes because it save my valuable time for other things.
Food for thought. And my two cents worth.
Dave