I started one a few years ago using an initial mix of ground up Kashi grains and flour. It was my first foray into using starters, and it worked pretty well. After sitting unused in the fridge for way too long, I decided to make some new ones to compare.
I did one using some whole wheat flour from Sprout's and pineapple juice in the early days. Pineapple juice is the way to go, IMO. The flour was fairly old, maybe 6-12 months. It got going, but wasn't nearly as vigorous as my first. Smell and taste of baked bread was very similar. It just didn't have much oomph.
So, I decided to try another. I used Bob's Red Mill Dark Rye Flour and pineapple juice for the first couple days. BTW, on both of these new ones, I switched to feeding using KA all purpose flour at day 2-3. This one hit the road with its wheels spinning. At only 5 days old it was doubling in a mason jar in only 2 hours. I made a loaf of bread on that 5th day, and it worked great. Taste is similar to the other 2.
From my notes:
July 22, 2010
Dough for single small disposable aluminum pan. Trying this:
.45 t salt
30g starter (fed ~10 hours earlier)
Combined at 6:15 a.m. Folded 4 times at ~45 min. intervals. Put in foil baking pan @ 11:15 a.m. In cold oven set to 375 at 1:00 p.m. Baked 43 min. Internal temp = 210 degrees.
Good rise, tastes good. Turned out to be the right amount of dough for these disposable small baking pans.
It's still working wonderfully, as the loaf I baked tonight attests. So, if your "wild" starter isn't suiting you, don't hesitate to make some new ones. Apparently there can be quite a difference in performance.
One of these days I'll try a store bought starter to compare. I just think it's neat to make your own.