Higher resolution don't automatically mean better picture.
I've said a few times in this thread,if you are watching something in SD,ie normal TV or DVD ,then you only have something like 476 lines of vertical information.Now if your screen is 1920 x 1080,to fit the SD broadcast or DVD onto the screen,it has to guess (called upscaling) what's in those remaining 600 lines or so,and that is when you get problems with picture quality.So therefore,a screen that's say 1024 x 768,like the Panny and Pioneer,only has to fill 200 vertical lines instead of 600 lines,so the picture will look better.
Also,you have to take into account the built in scaler of the TV's and the Pioneer and Panny have been consistently better than the others for this.
Unless you are going to use the screen solely for HD,ie Sky HD channels and either HD DVD and Blu Ray,then I personally wouldn't touch a 1920 x 1080 set,as they aren't very good at showing SD.