Handling
With their comparable turning radii, the Lexus ES 350 and the Grand Marquis quite certainly handle about the same into and out of tight spots.
Drivetrain
The Mercury Grand Marquis's engine is significantly larger than the Lexus ES 350's. Bear in mind that more sizeable engines may use more gas than smaller ones.
Utility
The Grand Marquis will definitely prove more practical than the Lexus ES 350 for those of you with frequent kid-cargo.
Convenience
You'll likely take the Mercury for a fill-up approximately as often as the Lexus ES 350.
Comfort
Taller drivers will considerably enjoy the extra head room in the Mercury Grand Marquis's front cabin compared to the ES 350.
The ampler interior dimensions of the Grand Marquis make it roomier for your passengers than the Lexus ES 350.
Dimensions
The Mercury Grand Marquis is considerably heavier than the Lexus ES 350.
The Lexus's tank is almost the same size as the Mercury Grand Marquis's, though the Grand Marquis's is a tad larger.
The Lexus ES 350 and the Mercury Grand Marquis compete for the same parking spaces.
Cost
The Mercury Grand Marquis consumes a lot of gas compared to the Lexus ES 350.
The ES 350 is substantially costlier than the Grand Marquis as far as MSRP.
Warranty
The basic after-sale protection that comes with the Mercury Grand Marquis isn't quite as generous as the Lexus ES 350's.