I'm gonna disagree about the kits. I never bought a kit and I can't tell you how many times there was a bit I wanted to have while coming up with some type of molding profile but didn't have it. That turned into a trip to woodcraft, who didn't have it, and then a last ditch effort to the borg to find that they don't have it either. Even if one of those places did have the bit, I would be dropping $20+ for it. Finally, I end up ordering it online and waiting 3-4 days for it, delaying my project. All for a bit I literally need to use for 30 minutes and will probably never use again???
I think the beauty of a kit is that you have a ton of options avaialable to you WHEN YOU NEED THEM. If you find that you keep using that bit over and over again, then that is a good time to go out and buy the better bit.
JMHO but I will be buying a kit for this very reason.