No lies from SGFOSFG. Miller's does indeed have a unique taste. Goes from extreme sweet to extreme heat. A very wide bandwidth of flavor.
The flavor reminded Spicy Food Guy of when he mixes the duck sauce and hot mustard from Chinese take-out to make the perfect condiment for egg-rolls (does anyone else do this?). With this inspiration, Spicy Food Guy waited until his next egg-roll encounter and brought out the Millers. Not that Spicy Food Guy likes to brag, but the fit was spot-on perfect. Millers also passes the classic ham and cheese sandwich litmus test.
Miller's is a unique Western Pennsylvania regional mustard, and according to all reports, Miller is a nice guy. Encourage him. Go get you some Miller's.