I have had my Regal for a month now. I have the black interior, compared to the competition the finish is more solid and very well built, the silver inside and soft plastic gives it a modern look that I like instead of the fake wood, the front seat are a little bigger than the competition but for me they are comfy and look great. The light blue light at night is also cool, and goes well with the black. I don't fiddle much with the controls, but everything seems intuitive and has ease of access and again is solid.
For what I don't like, I am honeslty not sure yet. I don' t think anything in its class and price range compares from what I saw and test drove that includes the Altima, Mazda 6, Sonata, Malibu and the TSX. I don't expect more than that for the price, as the BMW, Audi, and Lexus top models with leather cost way more.
I also tinted my car and have new TSW Nurburgring wheels installed if anyone would like to see I could post some pics.