I think shape wise the TLX has a more sporty compact look which I enjoy more but the styling of the TLX is borderline too sporty looking in a bad way.
Engine wise a the TLX doesn't seem really seem exciting until you get to the 3.5 V6 with 300 horse power since the 2.4 seems like the TSX. In the end I just don't trust Ford's EcoBost, a lot of problems with misfires and not getting anywhere close to stated MPG. I think this is a huge reason Honda has stayed away from turbo charged engines.
This is not to say the MKZ is a bad car, but not a car I trust out of warranty plus the MKZ has hands down one of the worse infotainment systems in the My Lincoln Touch system. The lack of physical buttons leads to poor response and makes anything out of reach. The screen system has a bad lag and icons are way too small. Overall this is the biggest complaint and what has stopped me from buying a new generation MKZ.
Comfort wise I don't know if Acura will be able to match Lincoln if the discontinued TL is any indication of how the TLX will drive since the TL was borderline rough for me. However Acura's handle great and I expect the TLX to do the same, which is an aspect of the MKZ Lincoln needs to work on.
Acura finally is coming to the table with similar safety features to combat Fords Blis system with camera and radar systems that have enabled safety features like low-speed automatic braking, lane departure warning, lane keeping assist, blind-spot monitoring and adaptive cruise control. Acura is finally catching up on their repuation of building technological filled cars since the new TLX will have a7-inch touchscreen display that controls 3D-view navigation functions, real-time traffic and a suite of smartphone-integrated apps and services such as Siri. My biggest complaint about previous generation Acura's was the lack of tech compared to the basic Ford lineup which offered some cool and crazy tech features you are only now seeing on Acura. With this being said the new tech from Acura on paper seems to match if not exceed the MKZ.
So in the end hate to say it but I would pick the TLX. The MKZ's My Touch Lincoln is terrible and all the tech features that Acura lacked compared to Ford the TLX now has. Furthermore while the 2.4 or 3.5 are nothing sexy or crazy, I am 100% more sold on their reliability and ability to match advertised mpg compared to the MKZ.
In the end would I trade in my 2011 MKZ AWD for a new 2014 MKZ? No because of the infotainment system woes and because the EcoBoost reliability. Would I trade in my MKZ for a TLX? No, because I don't think their is anything awe inspiring about the car. I am not a fan of the new TLX styling and the performance on paper doesn't seem game changing, however the tech is finally crave worthy, but not worthy enough for me to spend thousands of dollars to upgrade to.