Depends what you mean by bad. I have noticed these lines from time to time, because I have been looking for them. We are taking *very* feint lines in the background, against areas of primary colour. Not too distracting, and, if you find that they are, then connect equipment S-video and this problem disappears (pq is not much worse through S-video on this TV).
X-box picture is fab. TV - well, not as good as other sources, but if you turn most of the processing to min or off, it is perfectly watchable, and that includes low bitrate, fast motion stuff like football.
Just a few issues, raised elsewhere in the threads. TV seems to have a problem with 60hz/NTSC signals through RGB Scart. On Ext 1, picture displays as composite in 60Hz (e.g. X-box 60HZ, transcoded NTSC) or pure NTSC. On Ext 2 (the other RGB capable Scart), the picture displays with a really off colour balance - reds become blues, people look like smurfs, etc.

Now, I'm not sure if this is generic to the set, but I have seen posts which suggest it is. A bit of a pain, but, since nothing is perfect, easy to live with.
Minor grumbles aside, this is an excellent TV, and I'm sure you will enjoy it.