Hey:
I own a Casio WK3800. I bought it for practice, and to sometimes use at a nursing home where I play monthly. I might even use it at church. It is a good sounding instrument (76 key) but it is not well made. The keys make a clacking noise if you play on them with any amount of force. The keys seem flimsy, and seem to be subject to damage if handled carelessly.
I had the keyboard in my music room at home, and played it against a Korg Karma, and a Yamaha ES61. The sounds were very close when played through the same amp, (an accoustage Image "contra" 350 watts.) I mention the amp to allow that the instrument was played through a good amp during the comparison. The instrument sounds more like the Yamaha and the Roland digital piano that I sometimes play at church, than the korg. A korg sounds different from most other boards to me. (darker). But the quality of sound in the instrument was good, even played against the others. It sounds pretty good even through its own speakers.
The organ sounds were very good. You can change the sounds of the organs by means of electronic drawbars. I would play the organs on this instrument anywhere and not feel short changed. You can put batteries in the thing and use it portable, and it still sounds pretty good.
I paid $276.00 plus shipping and tax for mine from Sears.com on the internet. The total was about $310.00.
My biggest complaint is a perceived lack of quality of construction, and the clacking keys.
I will certainly keep the instrument regardless of the mentioned complaints.
berbie