I've never owned a 4:3 Sony big screen that I kept. I had two KV36-HS510 sets from bestbuy in '03. Returned both of them because of screen issues, that's when I decided to upgrade to the big screen route and ended up getting Toshiba 51H83 rptv. Loved it, but really wanted the Pioneer I still have. Sold the Toshiba to my sister, went to Wal-Mart who were the only ones to sell the iconic Pioneer SD-533HD5 and bought it. Use it to this day and wouldn't trade it for anything other than maybe another Pioneer, but those are pushing $6K.
The issues with the screen on the two Sony's I mention were one had tiny specs in the glass that were visible when the set was off. I paid $1600 for this set and I wanted it perfect. Tech examined and I got an exchange for another one. When I got the second one, I noticed the reflection of my window was curved in the glass when the set was off. I dumped that one too and got the Tosh.
The general chatter around here is that a large majority of big Sony tube tvs have problems in these areas of vertical and horizontal. If you can get past it and accept the sets for what they are, which imo is beautiful pieces of electronic gadgetry that in turn also produce still the benchmark for picture quality, then you will be fine. If you're expecting perfectly straight vertical and horizontal, these HDTV tube sets aren't for you.