I bought one with a regular-sized, third-pound patty for $5.39 (a "Big" half-pound patty is also available for a buck more).
The patty turned out really well with a nice sear to it and a juicy, coarse grind. The seasoning was very light so I got mostly plain beef meatiness.
The produce was all pretty fresh and was crispy, firm, and/or crunchy in the right places. The pickles in particular were very thick cut but not as sour as the smaller ones at most fast food chains.
The Smash sauce added a slightly mustard-y mayo quality and, when paired with the ketchup, still adheres to the standard burger condiments.
The bun offers a slightly dense, slight sweet flavor compared to a standard burger bun. It was still very soft and nice overall.
Overall, I found the Smashburger's Classic Smash to be a very solid rendition of the classic burger. The quality and execution are all spot-on, and I especially enjoyed the texture of the beef. I would go with the "Big" patty though, as it would better balance the other components.
Nutritional Info - Smashburger Classic Smash burger
Calories - 720 (from Fat - 420)
Fat - 47g (Saturated Fat - 20g)
Sodium - 1910mg
Carbs - 45g (Sugar - 8g)
Protein - 33g