Sir,
Trust me on this one. Go with a Kurz if you are an experienced player (operator). You will find new joy to be experienced with a fully loaded 2600. The 2500 is also an excellent electronic instrument. If you must use the transposition function, well what can I say... Hira, my teacher is 4 foot something - a little Japanese lady and she would wrestle you with that button to not do so. It also would theoretically disable your ability to play all the scaled modes properly.
It's a Zen thing actually so since this server is located in the western hemisphere, I will shut up any willfully take any beating with honor.
The Kurz WILL provide sufficient patches to modify for a pallettable piano and / or organ sound. As far as some of the effectos, an outboard unit of quality stature is likely to offer increased sound qualities. Nothing is impossible, but it's tough to get a sweet reverb without time invested in great outboard unit that typically costs ugh... REALLY GOOD outboard reverb units are expensive. I wish I couldn't hear the difference because then I could go on vacation twice a year instead of once with the money saved.
MORPH!

PS: A bottle of suntan lotion in Bora Bora is about $35.00, but you can save $20.00 by buying one twice as big for $50.00 if you use it a lot, however, it will not provide a useable reverb effect and I will never tell you that I am not weird.