It is not as clear cut as the two of them put it. The GTS450 has a few features that do make it favorible however it is not as powerful as one would like to think. It often under performs a standard gtx 260 and often trades places with the gts 250 in some games. Meaning that it isn't as great as the specs suggest. If you can scrape up a few extra bucks then go for a gtx 460 or a 6850. The GTS 450 can barely even compete with a 5770.
You are right about that.
Going for the GTX 460 would be better. The GTS 450 does beat the HD 5770 on some occasions ( rarely some, as I had heard )
Seems that only the overclocked or TOP edition of 450 GTS can beat the stock HD 5770.
I play a GTS450 and it's a great graphics card on the "bang for buck" front, and ought to give you a good performance at 1600x900 but as nforce4max has said, for another $40 or so the GTX460 will obviously be better.
Even I'm using an Asus ENGTS450 DC OC with just a dual core E5200 @ 2.5GHz Processor. I feel it's really great as it performs well with 1600X900 res that I'm using. 460GTS can be better. But I'm satisfied with 450GTS.