I have the Rigexpert AA-600 - it is awesome. FWIW, some of the local guys that run 440 repeaters have used this analyzer at repeater locations where there is quite a bit of RF from all of the various radio services. Where other analyzers have failed to work due to RFI, the Rigexpert AA-600 has worked without a hitch.
When I first got mine, the keyboard had a minor problem: The on/off key just wouldn't work reliably. I submitted a support request and a new keyboard was shipped out right away. Problem solved.
I love the ability to save analyzer plots and then later look at them in detail on your PC using the supplied software. I love being able to sweep 5 bands on a multiband antenna at once! In fact, I can't really think of anything I don't like about this unit.