I had a solid session with Kronos 61 the other day with a friend of mine. In short, I will say that I was underwhelmed by strings (PC3 definitely trumps those from my first-hand perspective) and HD-1 sounds in general. Damn, those were some lousy harpsichord samples, my X5D has them better done, and STR-1 one felt too synthetic. Also pizzicato strings were horrid in the upper range, they sound much better on my PC3K. Brass... eh, skip them.
I very much dislike the CX-3 distortion in comparison with KB3 on Kurzweil, which is far better sounding now since OS 2.0. However VB3 is IMHO still the best Hammond emulation there is, and I have it on my V-Machine, so I'm not bothered by that.
I know a lot of people on this board won't agree with me, but I don't care, really.

Synth engines are amazing, though. I wish I could get all of them in a separate box, without the other engines. One thing that I noticed, though, and I don't really like it, is that the resonance sweeps sounded virtually the same when bumped to the max, no matter which engine I was using. And no, it's not the monitoring system, the friend who was there next to me noticed the same thing. I was expecting more difference between the filters, but right now, I feel quite confused.
SGX-1 and EP-1 are pretty darn good, though. I wouldn't use Japanese grand out of personal preferences, but German one is sounding quite nice.
Physically, the data wheel is absolute crap, compared to the one on my PC3K8. That's no contest. Korg should fire the ones who thought this design was a good idea. Other than that, I feel that knobs are a bit too small, they could definitely be bigger in diameter. Sliders were very firm, though, solid response, a tiny bit sideways wiggle though. And oh for crying out loud, give me endless rotaries instead of fixed-range knobs already! It's a premium priced product, I want the goods. Endless rotaries are a much better solution than ordinary knobs when you have a flexible machine like Kronos. Korg, get to your senses and start using more endless rotaries on your future workstations!
Plastic sides are looking very cheap, and I don't like them one bit. However overall construction does feel very solid, except the data wheel. It was very light, which is great if you're doing gigs often.
Oh, there's one more thing I must comment on. I absolutely dislike the drum tracks feature, it should be turned off globally by default. I know I'm probably alone in this, but like I said once above, I don't care.

Overall: Kronos feels like hit and miss to me. Definitely NOT worth the 3000€ asking price over here in Europe. PERHAPS worth the price you guys are getting it for over there in USA, and I'm talking about the $2600 preorder price some of you got it for.
I'm gonna wait for Kurzweil's next big thing. And I have a feeling that Kronos isn't gonna be that tough a nut to crack.
Peace.