Things didn't start out well aesthetically today. 1A: Surrender (CEDE) went in without a second thought, unless you count the thought: "Oh, it's going to be one of those puzzles." Not an auspicious beginning, and I give it a C-. And indeed, shortly thereafter, I had entered ANON, ENNE (feminine suffices should be eliminated from the language entirely), HIRER, ERIN, and IFI, and I was not out of the NW.
If there was a silver lining to the increasingly dark cloud, it was 1D: One checking you out (CASHIER). I love that clue, and the word is very nice as well. Too bad it's accompanied by ENTITLE and DOORONE (I doubt they ever called it that on "Let's Make a Deal" - it should be "door number one").
Fortunately, we moved out of the NW. There were an extraordinary amount of words ending in -O: LOGO, ARNO (have I mentioned recently that I visited Firenze last year?), ESPO, ITO, ELNINO, VIDEO, NUEVO. TOO? SOO? And what are the Soo Canals? Apparently, they are artificial waterways connecting Lake Superior and Lake Huron, although Soo Locks Googles much better. Perhaps this should not have been a Tuesday clue.
The three corners not in the NW had much better sets of words. 45D: Written introduction? (NAMETAG) is cute. And we all like ASARULE, as a rule.
Oh, yes, the theme. All the long answers have a first word that goes well with "age"... "age"s well? Hmmm. Anyway, the best of these are STONEHENGE because Spinal Tap, and SPACENEEDLE, because "Space Age" is such an unexpected addition to the geological/prehistorical other ages. I would have liked the theme better if the clue for the revealer (69A: A very long time... or a hint to the starts of the answers to the five starred clues) didn't echo 39D: A very long time (EON). I feel that the revealer should be unique in the puzzle.
A lot of dross: AMS, PMS (right above each other, which lessens the blow), SRS, OSS, ENG, BVD, NENE, just to name a few. On the other hand I enjoyed the set of COLORIN, URGEON, and KEPTOUT. Probably a thumbs down on the whole, but just a little.