I just got my M92 two weeks ago and I absolutely love it. I have owned a DX in the past, but the M92 makes the DX look like a toy in comparison.
The M92 offers the full benefits of a 9.7" E Ink stylus screen and highly advanced firmware. The PDFReader app is great, and there are just so many different viewing options. Unfortunately, their user manual isn't very detailed, so I am not sure how to make full use of everything yet, but with some practice I will be there soon.
I also really love that an Onyx distributor regularly posts firmware updates and patches right here on Mobileread! I am not a very 'techie' person, so I love the chance to do things like load firmware updates haha. I really feel like Booxtor takes care of his customers all around the globe. Also, there are some very kind and helpful MR members, like Mono, who are willing to help troubleshoot.
I am from USA, but many Onyx users are still in Europe. There is a US vendor who sells the M92 on eBay, but for some reason they spiked the price up from $399 to $429 within the last two weeks. Maybe you should wait a bit until it goes back down.
Anyway, I am an Onyx customer for life. I just hope I will be able to purchase future models from a vendor here in the USA