I've done 4 kits so far, but I plan on changing it up soon and purchasing some ingredients and trying to make something on my own. I plan to buy a couple 1 gallon carboys and making a couple batches to test things out. I'll probably still do a couple more kits later for 5 gallon batches until I become comfortable with the brewing process and in really understanding recipes. I'd like to know I can brew good beer first from kits, then work on making changes. If you change to much all at once, it will be very hard for you to understand what you did wrong...and quite frankly you might get frustrated!
As far as I can tell buying kits from northern brewery (only place I've bought so far) It seems like what you get in the box, would be the same as if you just went out and bought the ingredients separately for that exact recipe anyway. Its just packaged easier for you, and you only get the exact amount of stuff you need (no left overs). So in a sense just using someones recipe imo is just like buying a kit. Moving up to the next level is completely designing a recipe on your own.
I really want to try an AG batch, but I need to spend the $ on the extra equipment which I can't do at the moment. But i'm in no rush... got my whole life to brew