I have the 6EXA, and it's great, but like the other guys say, it all depends on what your flying future holds.
For some people, the 6 channel set will be all they will ever need, for others, progress will require extra features.
Everyones different, so unless you know what your flying future will bring, then I would get the 6 channel set for now, it should see you through about 2-3 years at least anyway.
Then if you decide it's not enough for you, then get a better one later.

I started off on a basic 4ch set, but 6 months later found that I had outgrown it, and bought the 6EXA set, which I have now had for a year and filled 4 of the 6 memories.
I can't see me needing any other set for the time being still, so I can see this one lasting me a few years still as yet, as it does everything I need it to.
For most people the advanced functions that you get on the better models don't even get used until about 2-3 years of flying experience, where you get to the point of being able to make good use of them, some will dissagree on this, but there is stuff on them that a lot will never need, or not need for a long time.
Yes it's good to have lots of spare channels for seperate mixing, but not essential, the beginner won't see any advantage of it until a great deal of experience has been gained, so just using Y leads is highly commonplace, and acceptable.
If you ever need a two elevator set up, there are ways around it, by either using the custom mix on the 6EXA set, a servo reverser, opposite servo mounting (one facing forwards, one facing backwards), or even two different makes of servo that operate the opposite way to each other naturally (can't remeber which ones though, may be JR & Futaba)

The options are not all closed just because of a lesser enabled set.

Hope this helps, and good luck [sm=thumbup.gif]