Ooh, this was a tough Saturday. I'll point out some answers I'm unhappy with, but overall, who doesn't like a struggle on a weekend?
I entered through the ENSUITE, and followed with SAYPLEASE. At this point I thought things might be easier than expected. But I tried turnLANES for 1A: Places for drivers to get around (LEFTLANES). Okay, so that's actually a pretty darned good 1A. I'll give it an A- for the laugh, but a B for the fact that how many left hand lanes are there on a highway? Just one. So overall, that averages to a B+.
Anyway, I couldn't remember CALDERCUP, even though it was a clue on Thursday where it was called the Calder Memorial Trophy. So when things slowed down there, I moved via 21A: Engage in warfare (SPILLBLOOD) and LALO - how nice to have specialized music knowledge - into the SE corner.
I had TAKETIME and TREN as my entrees here. I like this corner a lot. 48A: Entertainers for whom lines quickly form (SLAMPOETS) takes the prize for my favorite clue today. But we also have two not so great answers in CASHAUDIT (I mean, I see that it's probably a thing, I've just never heard of it) and 55A: Producer of loose leaf notes? (TEATASTER). This latter is a real job, apparently, but looked to me as I entered it to be a completely made up vocation.
Anyway, the other answer in the puzzle I didn't like much was 38A: Consumers want to get their hands on it (TABLETPC). Oooooo-kay. I just don't think the clue really works.
Otherwise, the puzzle was quite smooth and well constructed. There's a mini-theme in Mexicana with ELMARIACHI, SOMBREROS, and LAREDO.