Difference between NFS Shift and Undercover? Which is better?

I have both and i just seem to enjoy undercover more. Undercover is more street racing and Shift is a simulation. Undercover is far more easier to play and control though and can be beat relatively quick while Shift takes a bit more time. Id still get undercover though

 

In short, NFSU = arcade racing, NFSS = sim racing.

Most people who have both games prefer NFSU, way more fun.

ps: This has been asked so many times. In fact, there was a thread just like this a couple of days ago.

Or you can check out the EA sale thread, heaps of answers there.

 

i have both of them, and
im liking more undercover.
In shift you only race,
in undercover there is cops, etc.