Kurzweil sounds better. Besides, there are TONS of soundsets available for the Kurzweil K2500 AND it can use EMU format, Yamaha format, Roland format (over SCSI), Akai format and so on.
The K2500 shines because it is also a sampler and not bound by the limitations of most other synths. The sound quality blows away the competition.
The XP30 is just as easy/hard to operate for any beginner as the K2500. While the XP30 is an okay synth, it's not remotely in the same class as the K2500 is. Not even close.
Sure its complex if you are delving into the FUN's and programming your own material but not for day to day operation or loading soundsets. It's precisely as easy as any other synthesizer. However, when you have mastered the basics the Kurzweil still has more to show you--unlike something like a Motif which is just average samples, paired up with fancy effects and a bunch of looping phrase samplers that's great for techno music, but probably not what the doctor ordered for this guy.