I have the BDP 450 which I chose after comparing with others. (Including more expensive players)
Have no problems with any discs freezing or not playing, however its media support is more limited than later models, plus Netflix is no longer available just YouTube and Picasa.
There are no analogue outs on the 450 so sound quality will be solely determined by whatever you have it connected to. (I use the Pioneer SLX 87 Receiver)
Build quality is quite good though making the Sony’s feel a bit cheap in comparison. (It’s a similar quality build to the more expensive Panasonic players)
When I bought mine it was a similar price to the BDP 160, although since I bought the 450 the BDP 160 price has dropped considerably, thus is probably now the better deal.
Hope this helps