For what it's worth both the Pa-600 and Pa-900 are being built in China whereas the top of the line Pa3X is built in Italy. Chinese production quality has improved quite a bit over the last 10 years I might add. Italy, on the other hand, is well known for producing top quality products with a focus of attention on detail. I have yet to play the Pa-600 or the Pa-900 because Guitar Center still doesn't carry them at any of the local GC's in my area. By the way, I noticed that Guitar Center is in big financial trouble owing approximately $1 billion to their creditors. I suspect that some of the keyboard companies are hesitant to ship their products to GC outlets because of the financial mess they're in. On the other hand Yamaha continues to ship products to the Guitar Centers in my area which is nice to know. I would have kept the PSR-s950 if not for the few minor inconveniences I had with it. Examples being the really cheesy keys, an inferior Vocal Harmony and being unable to navigate the keyboard buttons in low-light venues. Other than that it was a nice arranger.

Korg has just released the new Pa-300 arranger and from what I've gathered it's made in Italy although don't quote me on that. But it only has half as much WAV ROM as the Pa-900 but in contrast it has the same amount as the Pa-600. I've heard several people's opinion about the Pa-900 and most of what I've heard has been good. But there is a fly in the ointment where one guy said he actually sold his Pa-900 and bought a PSR-s950 and the reason he gave was the Yammie sounded better to his ears. To each his own I reckon.
I see Fran is still bragging about his G70.

For what it's worth I played the G70 and wasn't all that impressed. To each his own I reckon.
Arrangers being built today are superior in many ways but in other ways not so much. Case in point, the sound quality has improved quite a bit but the overall build quality has taken a hit if you ask me. Plastic, plastic, and more plastic and the internal components have also taken a hit in some ways too. For instance the PSR-s950 Vocal Harmony components are inferior to the Tyros 1 which I owned but sold a few years back. I also think the Pa-900 VH ain't the greatest either although it's somewhat better than the Yammie in my opinion. Hopefully the Pa4x Vocal Harmony will be a step above the Pa3x but only time will tell. 256 note polyphony would also be a game changer but for whatever reason the Big 3 has milked 128 polyphony for all it's worth and therefore we might be stuck with 128 for another decade or longer which is just plain wrong in my opinion. I have harped on doubling the polyphony for a long time now but it keeps falling on deaf years for the most part. Ketron has upped the ante and Roland actually doubled it on the Jupiter-80 but it's a synth, not an arranger.
PS: Fran said it's been too quite around here so I thought I'd chime in. Glad to see our good friend Don Mason is back on his feet. Bypass surgery techniques have improved quite a bit over the years and so has the recovery time. My advice to Don is stay healthy and a big part of doing that is eating healthy.
All the best, Mike