At least for me, the GRE radios are somewhat better for searching the federal bands, in that it will detect analog tones or P25 NACs automatically. The Uniden radios make you choose between searching for tones or NACs.
I think the programming between the two can be easier for some than others. I think the programming on the Uniden radios is a little easier to do on the fly by hand than the GRE. The form factor of the 396XT radio is great for portability.
Both the GRE and the Uniden radios have their pluses and minuses...
- Chris