Hi;
I have never owned a ts480 but I have been long considering the purchase and 
will give you the info I have accumulated.
The ts480 has room for two filters as opposed to the one in the 570.  This 
may or may not make a difference.
Secondly, it gives you some additional audio feedback that is not available 
with the 570.  It speaks the power setting and mike gain settings.  I 
believe it also gives you a beep which actually tells you the status of the 
speech processor.
The real question for me is the dsp any better than the one in the 570? 
They are both audio dsp.
You also have to consider that the 570 is one box where you have two units 
with the 480.  There is supposedly a unit that holds the two together but I 
suspect it may be hard to find.  Also kenwood has made things difficult in 
that they changed the power cord, microphone plugs and probably the 
accessory plug for an amplifier.
The other thing is that if you elect to buy two filters and the microphone 
plug adaptor the difference in cost between the ts480 with accessories and 
the ts2000 is less than $400.00
I will be curious to know what you decide on.
Richard