I have been using a 480 for the last 5 years as a base and was quite happy with it's performance except for no 2m/70 bands.
Just bought a new 2000 about 3 months ago.
Here are the general differences I see between them.
1. The TX bandwidth is 3000 vs the 480 at 2800. A plus in the audio department with a good mike.
2. The 60m band can be activated on the 2000 and stored in memory for fast accurate access vs the 480 that can tune them out of the box and/or store in it's memory the same way.
3. The low and high cut is a bit better on the 2000 and a bit easier to use.
4. The S meter is a lot more 'stingy' than the 480.
Actually the 2000 is more proper being closer to the standard of 50 uv = S9.
Beyond this the common features are about the same except for the special features the 480 does not have being a mobile/base design.
Both hear about the same sensitivity on an A/B test.
Both use the Kenwood control program both use the HRD control program, both use the memory control program.
Some other differences, the 480 still uses the 2sc2897 finals, the 2000 uses FETS..
2m and 70cm bands does not have an SWR meter function on the display.
Both actually display both peak and average power at the same time on the display by watching the last bar action in the display while the rest fall back.
The 2000 actually has a band scope similar in operation the HRD control program..
Both have the same RX and TX audio EQ and User setting to load in your own custom audio response curve as you design it in the Kenwood control program and down load the file to the radios.
2000 has dual receive and S meter bar reading second rcv on 2m and 70cm only.
2000 is equipped for data modes and satellite.
2000 has a separate antenna receive jack for HF turned on by menu option.
2000 has separate TX/RX antenna connectors for 2m and 70cm antennas or Diplexer use with a single transmission line to a dual band antenna.
Remember the 2000 is an older design that has so much capability that has kept it going as the top of the line before the new 590 and now the 990.
If your not demanding on absolutely the best selectivity for contesting, dual receive etc then this radio fills the normal ham radio uses otherwise you have to pay the price for anything better with features you may not use.
Good luck.