USRPs best/worst features

Hi guys, I would like to have some opinons and techincal detail on USRP
and
USRP2.

What is, to your opinion, the best and the worst characteristics of the
USRPSs? What I should expect buying the USRP2, as a difference from the
USRP1?

What are they’re main tecnichal detail (noise floor,
decimation/interpolatuon
avaibility, transmission filter designing…)?
And is there any other piece of
hardware that can be used as the Hw RF frontend for gnuradio?

Thank you a lot
for your answers

Of course links and opinions are more than welcome.