What's the Difference - from teaching, learning, and Musician's perspective? Some semi-random thoughts.

1. There's nothing like playing a well-maintained concert grand. NOTHING.
2. But few people have access to a concert grand, much less a well-maintained one.
3. The new Roland V-Piano is supposed to come close, though. At roughly $6,000 it's a lot cheaper than a quality grand, but you're going to have to invest in some amps and speakers.
4. Keyboards/Synths give me capabilities that a piano doesn't - different sounds, etc.
5. I play a Piano and a Keyboard differently - even when the keyboard has a great action (like my Roland RD-700 sx).
6. I'd suggest learning the Piano, and integrating the "keyboard" part of it as a part of the process. To play keys you need to learn how to work your buttons, how to change what you play depending on the sound you're using, and how to improvise a part while looking at a chord chart.
7. Best way to learn how to change your touch? CLASSICAL PIANO music! (especially Classical, Baroque, and Romantic eras).
8. To Comp (i.e. accompany) you need to know your chords and scales. Those are the tools that let you combine bits and pieces into something interesting that fits the song.
9. This is true regardless of the style - rock, jazz, pop, urban, country, world.......
10. You still have to practice - every day is best.