We were a little nervous starting this one on the iPad after the "... there are elements in the print version that cannot be duplicated electronically" warning, but we pressed on! It seemed like a fairly straightforward rebus puzzle, but we didn't know what to make of the circles. I've read elsewhere now that in the print version there is a slightly darker horizontal line between the two parts of each vertical two-part answer. (And by the way, those triple-fifteen edges look great!) So, the circles, instead, indicate the start of the second part. That's all, and frankly, it hardly seems worth it, except that it is a little reminiscent of the bubbles you might see between the oil and water in a salad dressing.
As for the puzzle, the fifteens, although they look fantastic, they were a little less than scintillating. CAPTAINLASTPASS (1D: ____ America/Final maneuver). "Last pass?" What's that? Final edit, maybe. Final 'Hail Mary,' maybe. I liked "wheelie," but the rest of them just seemed kind of blah. Not bad, but, well, I don't know... maybe I was expecting too much.
The rest of the grid, on the other hand, I thought was above average, especially the threes. 11A: A train (BCD) - clever. 14A: Times column: Abbr. (ARR) - tricky clue for a common answer! 39A: Cow, perhaps (AWE) - a nice twist. And everyone loves MEL (6D: Blanc who voiced Bugs Bunny), and YAZ (55D: Longtime Red Sox nickname), right?
The center was the toughest, because it took forever for us to see those last two rebus squares. I had "fRyER" in there for BR[OIL]ER (34A: Chicken for dinner) for a long time, and "Two- or four- seater, maybe" is a damn tough clue for MAITRED ("maitre'd").
Lastly, had tap[WATER] instead of ICE[WATER] (50D: Restaurant freebie) for a while, and learned that ALA is, apparently, the "55D: Yellowhammer State: Abbr." whatever that is. (It's the state bird.)