Great sound. Also with sound effects like car chase sounds etc. Am still learning all the sounds. Lots of really interesting sounds (voices) eg Asian bells, South American instuments. Very easy to dial the different voices. There are over 700 including sound effects. Groove samples are very. Inspiring.
Headphones are great. Sounds like you're listening normally - Hard to believe the sound is coming through a headphone. It is a really good quality headphone. For most people I think the headphones are essential.
I did not get the stand. I use a table which works OK but stand probably better. Just can't figure out how my legs would fit under the stand.with the X bars but people seem to manage.
It's fairly light and is reasonably portable but it's large (76 keys) Would not want any bigger. Could easily carry in a car. but need two hands to carry it. It would be good if it came with a carry bag. It would be light enough to carry with one hand then. But then again I only use it at home.
Unlike concert keyboards it has built in speakers.(with excellent sound).
Have not had a chance to try everything yet. but love everything about it.