Both are good and reliable vehicles. But, I lean toward Lexus more.

Lexus, all day long.

Get the Lexus.

Between the two, and if you plan to keep as long as possible, go with the Lexus.  Realize that Acura ILX has an 8-speed dual clutch transmission and will not be as reliable as the  Lexus 8-speed conventional automatic transmission.  Also that Lexus’ engine has both port and direct injection so the back of the intake valves (of the engine) are cleaned off and not susceptible to carbon buildup.  But the Acura is direct injection-only and over time can have carbon buildup (which will require catch can to mitigate and periodic cleaning of catch can and the intake, which is just more maintenance and cost).  Peace of mind = just go with the Lexus.