I sure did and to cut a long story short I ended up with a 300 euro loss.
I never even made the move from PA800 to PA3X due to the fact that all of my programming on former models with strong emphasis on the PERFORMANCES became virtually useless in the PA3X and ensuing models.
I do not want to hi-jack this thread and would like to emphasize that both sounds and styles on the PA4X are excellent. That being said there is no excuse for the massive number of bugs that Korg is still working on and the complete overhaul of OS. We have had the discussion on the disappearance of Performances etc.etc. no point in going there again.As I do not perform publicly and have ample time to program a song arrangement at home I have always felt very comfortable with the PA800, which to my mind is a great and intuitive machine despite the fact that it lacks the improved samples of the newer machines. An added bonus is the fact that the internal amplification and matching speakers in the PA800 are simply fantastic ( the best I have ever come across in any speaker intergrated arranger keyboard). Just compare the PA900 to the PA800 (John) and you know what I am talking about. I now run the ketron SD1plus thru the PA800 and it sounds great.
Thing is that the ketron too needs intensive in depth programming and the OS is not as intuitive as one would wish ( I am sure the Italians had a big say in the new OS on the PA4X) but I had other ketron keyboards so I will find my way eventually.
From day one of being on this forum, nigh on 16 years now I think, I have always subscribed to the view that it is better to have TWO arranger keyboards of TWO different brands,based on the assumption that they will compliment one another. And of course on the assumption that you will not have to lug them about for gigs. I recall that in 2001 I owned the now obsolete Roland E70 (great ac. piano though) and the Korg PA80. Subsequently I would think that if money is no object these days one would choose for the Korg PA4X with either the Ketron SD7 or a Yamaha Tyros 4/5 or , more conveniently PSR970.

All in all I think we are truly pampered if it comes to choices.Buying second hand you can now have pole position for a relatively small amount of money and the possibilities of the current range of keyboards are endless. Again and again I find myself dumbfounded by how little many users know about their machine and how little they have managed to exploit their arranger keyboard to the full.
In addition for me ( as mentioned ) there was also a financial impetus.Anyhow I am pleased with my current set up though it looks like it won't be used all that much with summer ahead.
One final observation also to get back to the core of this thread, the KORG PA4X, is the inclusion of Keyboard Sets instead of Performances. Keyboard sets contain a mixed bag of righthand sound/ sound combinations. I always wonder how many sounds you actually want or use for the right hand ? I mean if I give you 10 or 20 acoustic piano sounds to choose from on your arranger would it not be fair to assume that you will probably use 2, 3 at most all the time ? Same for other natural instruments such as sax,organ, electric piano, brass , etc. But even if you were to use say 5 or 6 out of each category ( apart from the fantasy and synth department) you would probably be having a hard time getting in excess of 50 or 60 overall sounds ? My point ? I don't need Keyboard Sets, hell even the 12 year old ketron SD1plus has a section where to stall 80 (!!) favourite sounds, be it factory, user or layered sounds. It is not the quantity that counts but it is the quality imho. Anyway enough said, I will continue to follow all of your views and endeavours here on the forum with great pleasure and hopefully I will master the ketron by the end of summer and record some good stuff during autumn /winter.

kind regards,
John