Forget MPG with the CTS. IS350 is okay but I think a G37 will beat it. I don't know much about the Acura TL.
Acura TLs have entertainment systems if you have kids. Comes standard... No amount of money can buy that in a G37 for you (at least not factory, there is after market options...).
G37 will get better city and highway MPG than the Acura. Acura gets below or around 18..
TL is all wheel drive right? But it the G37 does 13s... Dragtimes.com says the Acura TL is really slower than 14 seconds. Some don't get over 16s. And my wife's scion TC does low 15s high 14s...
IS350 does the same times the G37 will... 13.8.
IS350s entertainment system is optional, and will cost you if you want it.
IS350 turns better in smaller spaces (sharper turn radius).
PERSONALLY, all statistics aside. I've ridden in CTS', G37s, and IS350s (I have not ridden in TLs).
The G37 was a standard model. Was not an S model, and we went over speed CUSHIONS (the HUGE ones that will fck you up if you go too fast over them) at like 50mph, and the g37 took the ENTIRE impact and we felt almost NOTHING!!!
G37 is a phenomenal ride. Speed bumps are annoying as hell in my wife's tC and in my fiero... But in a G37, they practically don't exist and I wouldn't even slow for them. True story.
CTS is expensive, maintenance heavy, expensive replacement parts.
My friends work at Crest Cadillac and Infiniti, and I worked at classic BMW as a valet myself. I've gotten to drive a lot of cars and put them to the test (even if they're only there for service lol).
Acura TL if you just want entertainment via gadgets.
G37 if you want the rest of it.
I am not biased towards either of them. I'm a Fiero guy. Those 4 cars are the same to me by name and brand... But if I had to choose, it'd be the G37 from the experiences I've had.