Depends on what you want to do with it. I'm a bit concerned about two of the specs. First, it only supports 24 notes of polyphony. Second, it only plays two sounds at a time. Whether or not these are important factors for you is dependent upon the style of music you perform and what you want to do with the keyboard. Also, as a modeling synth, you may not be able to play those really nice piano samples that you want. If this is your only synth, that limitation may be a bit much. But if you're adding to an existing synth, then that's less of a limitation.
If you want to ask other people who play it, you could go to Korgforums.com (
http://www.korgforums.com/forum/phpBB2/viewforum.php?f=70), which has a dedicated forum just for the KingKorg. Admittedly, the people posting there all decided to buy and play one, but you'll have the advantage of their experience.