No experience with either but do have experience with Dell's customer/warranty support and will never buy a Dell product again.
Pretty in depth reviews of each.
LP2475w
U2410
And the U2711 for good measure.
I would look at prad.de reviews, they are pretty much the only site that actually uses an i1Pro, or at least a generic DTP94b wide gamut conversion. Flatpanels and for sure TFTCentral sometimes get some weird gamut/white point results for monitors, TFTCentral is absolutely totally off an all of their gamut/white point measurements on wide gamut monitors since they use a non-modded i1D2 with software that applies no compensation.
Surprised to hear about you bad experiences with Dell warranty/support. They were amazingly good about taking back and offering full refund and shipping when I purchased a 2405 that had major overdrive problems (they eventually solved it months and months later with some later revisions). No problems at all, one call and it was taken care of. I had a great experience with them. Samsung on the other hand, wow.... By far the worst, most disreputable, dishonest 'service' I have ever had to deal with, lied and gave me the run around for almost two straight years, had to threaten them with filing with the state Attorney General. If you google Samsung you will find that they have already gotten in trouble in many states and have a worse than terrible reputation.