I have both a 2950 DX and a 6900 F25
They have both done a great job for me.
One thing that I think the 6900 has over the 2950 in a mobile setting is the capability to reach down and "click" channels. I know were the radio controls are and I know if I move up a band, or over so many clicks, were I am at without looking at the radio. The controls are layed out better (for me) in that environment.
On the Base, the 2950 is good because you can look at the frequency display, step under the digit you want to change, and move up and down quickly. And I can deal with the sometimes awkward to adjust inner/outer knob controls( I sometimes suffer from fumble finger with real close controls) in that case.
2 cents worth...
73
Jeff