need to reread the first one now that I have the anniversary reprint; it seems that the earlier printings were rather heavily bowdlerized to make it more YA-friendly, which might explain part of why Psion seemed a lot more disjointed and shallow than the other two books.

There are noticeable differences not only in language, but in plot-content. It's bizarre. I originally discovered Psion when I was in middle school, at which point it read fine as a YA, but I much prefer the original (reprinted) version, even with the cover issues.