To start with let's get the comparison of In and Out burger out of the way. The Actual burger and fries at In and Out burger are better.
The Burger at Shake Shack is good and I enjoyed the added bacon (hard to go wrong with bacon) and the peppers and shake sauce. The crinkle cut fries are okay but not fabulous. I didn't partake in a shake but did have the frozen custard (ice cream). I had vanilla with hot fudge. The ice cream custard was tasty but they seemed to skimp on the hot fudge.
Overall not bad, way better than the Mickey D's, Wendy's, Jack in the Box, Burger King but it doesn't top In & Out.