There are 6 plasma sets 50 inches or bigger in size being sold at Circuit City, and the customer reviews are generally not favorable to an even more expensive Phillips 50 inch set, which is nonetheless likely to be very similar to the model being sold at Costco.
For what it's worth, customer reviews of electronic equipment at Circuit City are generally of high quality, listing pros and cons and using a common ordinal (rank) scale between 1.0 and 5.0. Two Hitachis rank the highest, followed by the Zenith 50 inch, , a Samsung, a Panasonic, and an LG, with the Phillips in last place. Click on the yellow grading-bar and you will be taken to the individual reviews by the customers who evaluated their sets. Note that the Panasonic was ranked 5.0 in picture quality --- or close to it --- and got lower results overall because of its sound features. The Hitach 55" is very highly rated, but only by about 10 customers (the last time I looked). The Hitachi 42" gets very high marks too.
The Zenith set is the big surprise, very highly ranked considering its price, with the customer evaluations suggesting that they find the set a real bargain.
(i.) I saw the Phillips earlier today at the local Santa Barbara Costco, and the picture quality of the Maxent 50" X3 seemed clearly superior, though I agree with the posters who say that you can't really tell much from Costco's displays . . . what with the atrocious hook-ups there.
(ii.) A tag-on observation: in the Maxent forum, there is a link to the new plasmas that it will be bringing to the market soon, and so those seeking the existing X3 might want to wait and see what it looks like.
(iii.) Another tag-on come to think of it: Costco was also displaying the 42 inch Panasonic EDTV, priced at $1699. It had the best picture of all the sets there, including a Pioneer 43 inch not far away. Too bad it doesn't come in a 50 inch size. It would be a wonderful transition set during a period of relentless technological turmoil, what with all the changes in various HDTV's, Mpeg receivers, emission quality from TV stations, satellite and cable connections, and breakthroughs in LCD and, more important, SED based on CRT quality display . . . the latter touted by even the head of Panasonic US as the most promising dominant technology of the future.
(iv.) For what it's worth, the Maxent 50 inch --- whose speakers are removed --- was the handsomest of the sets, except for the 43 inch Pioneer.