It seems to me that if you just want to duplicate what AP can do for you, and you aren't 100%sure of your skills at such a project, the difference in price doesn't seem worth the trouble oh its own.

To me, reasons to go diy would be that you want something specific that's different; you need it sooner than AP will deliver; you know you have the skills and equipment to do a good job reasonably efficiently and with a minimum of fuss; or you just like projects like that and will find it rewarding for its own sake. If none of those things is true, just save yourself a lot of trouble and buy one.