I'm surprised an FT-897D costs less than the used value of a TS-450S.
But anyway, in "comparing" the two, the 897 would disappoint me only in that it's a very small rig with very small, and very few controls. As such, most functionality is menu-based.
In using the '897 personally (and I have, for days), I found it annoying that some of the most-used controls -- ones that I adjust constantly, from QSO to QSO -- are menu embedded. I like to have an analog front panel adjustment for mike gain, power output, speech compression level, keyer speed, etc. The larger Kenwood has this, the smaller Yaesu doesn't. The '450 also has a large, easy-to-read display, which I can read from across a room. The '897 doesn't.
The TS-450S/AT also has an internal and very good automatic antenna tuner, which the stock '897 does not. You can add an optional tuner module to the '897, but that adds considerable cost (like >20% of the cost of the rig).
I guess it depends how you actually *use* the rig.