They do perform well, A base TL has 285hp, is super comfortable, handles well, gets good mileage, and is full of modern tech for a decent entry-lux price. But as MagicRat said, it's a shame about the ugly face on all their new cars.
I've been saying this since they started this new Megatron look - and now the shield-face has infected the entire lineup, ruining just about all they had going. And what will that metallic plastic shield look like in 2 or 3 years, after all the highway stone chips have littered it with scratches and stone chips? To be honest, it looks better in person, but it's still a shame. It's like walking up to a supermodel from behind and seeing her gorgeous figure, then she turns around and has a hideous face...it just won't do.
But for all the things Acura is doing wrong, Infiniti is doing right. The new G37 is gorgeous, inside and out, as is the new Nissan Maxima (although that gets mixed opinions). If Infiniti had more base model cars to compete with the CSX (Canada only) and the TSX, that would help out their sales volume in the B and C segments.