I don't have any experience with the Continental, but last month I picked up a spare set of rims with the Falken 452s and boy are they noisy and rumbly at 20mph, 40 mph and 60 mph!
I came from almost new Potenza Pole Positions, and I trying to decide if I should have the Potenza's mounted on my new OEM rims.
The 452 also have no grip compared to the Potenza's. With the Pole Positions, I could barely break traction, with the 452s, I roast the rears at anything above about 70% throttle from a standstill.
I'm sure the 452 will last a long time, but they are *very* noisy/rumbly compared to the Potenzas!
Have you done any price comparisons lately? The Potenza's are about twice the cost of the FK452's - so I'd expect nothing less than for the Potenza's to perform phenomenally better than the Falken's. Not to mention the treadwear rating - <200 for the Potenza's vs 300 for the Falken's. Just playing devil's advocate here. The equivalent Falken tire would be the RT-615K. Unfortunately, the largest wheel size them come in is 18", true of any serious performance tire.
To the OP, the Continentals are definitely a far more sophisticated and better tire. The Continentals are in the same class as the Michelin PS2, which are arguably one of the best tires around for a daily driven M5. If you are getting the continentals for the price of the Falken's, I'd definitely take that deal.
I've had the FK452's on my G35 for some time (have had more than one set), and while they are a bit loud, they ARE a great tire for the price. The tire stays relatively consistent in all aspects (performance and ride quality) throughout it's life. It's a pretty good daily tire unless you are really picky about road noise.
On the other hand most forum members note that the Continentals get rather loud as they wear, but in the end I think all will agree they are a better tire than the Falken when value is not a factor.