This is probably my biases, but I'd recommend the YPG 235 over the other two.
Why? More keys. And weighted, too.
More keys is less important, given that the other two keyboards are both five octaves, which is (in my mind) the minimum you should get for an only keyboard. (If you're going the Rick Wakeman route and playing a bunch at the same time, then the size of an individual keyboard is less important.) But an extra octave or so gives you a little more space to spread out, and to split the sounds, etc. (The traditional piano keyboard has yet another octave of keys, with a total of 88. The entire range is almost never used.)
What is more important is the weighted keys. This is probably because I come from a piano background, but I find moving to lighter keys when I'm used to playing heavier keys is much easier than going the other way. Piano keyboards have a much heavier action than organs, etc. So getting your chops up on a heavier keyboard will, in the long run, make you a more flexible player.
But I'm sure you'll get other opinions from the other members of this forum, most of whom are far more knowledgeable about your options. Just because I responded first doesn't mean that you should give my thoughts excess weight.
