DON'T SUE US
I kept on wondering what the theme was. Even as I filled in answer after answer, with the down entries forcing all those Rs into the little circles. About halfway through, I looked back. Aha! All of the first parts of the theme answers are trademarked names, thus requiring the circled Rs. Which, by the way, you can use only once the US government has granted a registered right. The "TM" is for unregistered names, and anyone can use it.
My favorite of the theme answers is TEFLONRPRESIDENT (even though it required adding "the" in the clue), simply because it's the only one where the trademarked name is used outside of its usual context. POPSICLERSTICK, for example, refers to the sticks in the frozen treats, and XEROXRMACHINE to the most common usage of the company's products. It would be hard, but not impossible, I imagine, to come up with 6 other phrases that match the interest of my first example. FRISBEERGOLF is fine as well.
Outside of these issues, it was a pretty darned good puzzle. It went quite fast, as I finished it in about 75% of my usual Sunday time (in large part because there was no real "trick" to the theme answers). There are two excellent 14-letter down answers, SUNDRIEDTOMATO (nice clue: Ingredient that's been left out?) and LOOKWHATIFOUND. Also another 13-letter answer, ROMANEMPERORS, which has the unnecessary plural justified by the clue (Source of the names of two months).
Other things I liked: OREO and HOHO saved by the black-and-white and brown-and-white matching clues; HIJINKS, because it's just an awesome word; CORTEX and TOE, two anatomic answers that weren't gross; and 96D: Crime stories? (ALIBIS). There were plenty of iffy partials, crosswordese, and ECARDS, but not so much that it bothered me.
What did bother me? 1A: It returns just before spring: Abbr. (DST), which I give an F, because I had to wake up early today to drive back from DC, and that lost hour of sleep was really annoying. Timeliness only hurt this answer!