I used to stop in at Cooper's every time I was anywhere near Llano. It was always a special treat to look forward to. But, after a couple of sub par (yet very expensive) meals I've stop going. Haven't been there in a few years.
I think they've fallen prey to getting too popular. They can't really watch the pits like you're supposed to because of the volume of product needed to keep up with demand.
Their old pit boss opened a place near Spicewood on HWY 71 called Opie's a few years back. The BBQ reminds me of how good Cooper's used to be, plus they have excellent sides.
Of course, none of these places compare to the awesome BBQ served up at Hotglue's and Flamingo Babe's Gathering of the Fools. Now that was some BBQ to write home about...
