Sony displays do a good job of upconverting SD DVD. Pioneers and Panasonics do as well.
Mitsubishi DLP's absolutely suck at scaling SD.
BD player upconversion varies from player to player. I didn't even say mfgr. to mfgr.
Good upconverting Samsungs
BD-P1200
BD-P25xx
BD-UP5000
Not so good upconverting Samsungs
BD-P1400
BD-P1500
The LG BH200 is an excellent upconverter. The BD300 is not so much.
Sony and Panasonic models widely vary as well.
Until Oppo comes out with a Blu-Ray player nothing else can touch the 983 in terms of SD DVD upscaling performance. However, if you have less than a 65" screen, you won't notice much of a difference between the Anchor Bays, Reons, Realtas and Marvells in real time viewing.