Healthy competition is always a good thing.
Being two separate entities means they will continue to work in different directions within the same industry, coming up with new ideas and better ways to do things, all the while pushing costs down thanks to the other's presence.
Smaller groups banding together to make mega-corps aren't always healthy for the end user, especially when it comes to price. I think in their current forms they are both doing excellent work for the community, and should stay that way.