Evaluate where you will be using them and how often.
Do you camp a lot without hookups?
When you do, are their others around that you need to be quiet for or are you out in the middle of nowhere by yourself?
Do you camp often in the heat when you will need the A/C?
Can you carry the 3000 easily by yourself? Do you always have help if not?
All of these questions should play into what you get. The benefit of the Honda 3000 is the much larger gas tank.
The benefit of the 2x2000 is if you will only need one sometimes (no AC needed), it will save you some gas.
There are much cheaper alternatives (Champion 3500/4000) if noise is not a big issue due to only needing gennys at events where others will be running loud gennys (Nascar camping/Music festivals/etc.) or where you will be camping in places that would not distrub anyone.
I've not bought one yet but the Honda's are certianly the favorite on this website for those that can afford them and need to have a quiter genny.
Good luck in making your choice.