I'm curious about the powered monitor vs. All for only another $199 (the price of Logic Express) But yes Synthogy will work all by itself. I was trying only to point out that once you add a computer all kind of options become available, like recording and producing music, doing multi-track recording and so on. You are right about not needing any other software. see here for some of what you can do with it. I use "Logic" and Synthogy can work well with Logic. If recording is a goal then a computer is almost a requirement, non-optional. Which is best depends on the goal, is it playing just for your own enjoyment or do you want to record your work. But is not as easy as just playing a acoustic piano.
SYNTHOGY IVORY 2 UPGRADE
You can upgrade the sound as technology advances forever and you can record and mix and cut CDs and so on. The computer setup is more complex than just buying a DP but you gain flexibility. You have to do the audition with music you know well. Bring a CD recording of a solo piano concert to the store and listen to your CD. Powered monotor speakers will cost anything you want to spend. Likey cost for the box is $150, give or take $50. Some USB audio interface contain the midi interface all in one box. The computer send the audio to that interface and then you need a pair of good powered monitor speakers or headphones. Then the computer and software renders the sound and you will need a decent USB audio interface.
Next you need a Midi to USB cable or interface for about $50 so that you keyboard and pedal data can get into the computer. If you are buying one just for this the Macbook Pro would be ideal but even a cheap Windows PC could work.