For background I've driven almost exclusively DTS and Deville my entire life minus one Escalade and the only other car I've ever owned was an 85 Lincoln Town Car (everyone is entitled to one mistake). My first Cadillac was a 77 Deville and I'm 34 years young 6'1 210 and currently own a 2009 Escalade and the last year of the DTS with a Platinum package (2011).
Getting in the car its immediately a different feel. The seat and the contours envelope you like a good sports sedan would. The touch screen takes some getting used to but its workable. The peripheral vision is second to none, absolutely fantastic you can see all around you with little to no obstruction. The vibrating seats when you drift into another lane are pretty cool as well. The V6 is well, a V6. A little disappointing on the highway but not terrible. A veteran V8 driver will notice however. Whomever designed the steering wheel should be shot. If you have large hands as I do you will hate the button bumps especially on the right side of the wheel. I understand where they are going because the menus look nice but the buttons especially the ones for the menu that you will hardly use should be on the back of the steering wheel and out of the way. The seats are nice but more reminiscent of an LS430 or European style seat. The ride is decent with more of a CTS feel however but excellent handling.
Overall this is a good car and a worthy successor of the STS but this isn't going to cut replacing the flagship DTS anytime soon if you've been a long time driver of that model.