The only time a 2000eu will be quiter than the 3000eu is when they are both idling and no load on the 2000.The slightest load on the 2000 it will start climbing fast.
I have the 3000 and love it yes they are heavy but worth it.I have heard two eu2000s linked together running and a/c and they were noticably louder than my 3000 running mine.
The downside on linking the 2000s is you will need to go out and refuel often or get the long run tanks.If you go that route now with the 2 gens and tank its now taking more space than a single 3000.I can get atleast 13-14 hours running my a/c on a tank of fuel.