Holy Cow is that a broad question to answer or what??
You would have to be a great deal more specific - using what antenna, what freqs or freq range, etc. However in general, from what I've read, the 197 is more sensitive than the Unidens. That is, of course, a double edged sword - the Unidens tend to resist overloading a bit better.
However there are many other factors that go into hearing skip on the VHF/UHF bands, and while that's one consideration, there are many others. There are certain conditions that can cause these freqs to skip, and even a Uniden will hear them when they occur (I've done it myself with my 396).