Here are my first day impressions of the 360 Plus. The form factor is the same as the original; so I'm already feeling at home with it.
Buttons: The big mickey mouse buttons on the original 360 have a loud click and require quite a firm press to activate, so I was interested in seeing if there were any changes. The Plus version still has an audible click, similar to pressing the direction button, but requires a much softer press to activate. The difference is significant enough that I find myself using the mickey mouse buttons by default now, where I would rarely do that with the original.
Themes: The same themes work for both 360 versions, so I was able to load my favourites without any issues.
Fbreader180: I really enjoyed being able to fully customize my old 360 and got addicted to the wrist flip to change pages. Unfortunately this wasn't as easy a transition to the Plus version. The firmware is 15.4 so I tried the original fbreader180 software, no go the programs wasn't recognized. Once I installed "fbreader180-app-fw2.x.x" I got better results. I am now have access to all the same options as before font/margin/line spacing/etc. However, even though I have the options for 'page turn' I am not able to change pages with a wrist twist.
Dictionaries: I was pleasantly surprised to find the Websters 1913 dictionary already installed on the 360+, one less thing to fuss with.

The following dictionary files are installed:
- English_English.dic
- English_German.dic
- EngRus_korolev.dic
Calibre: Currently the 360+ isn't recognized as a device in Calibre. I was able to transfer books to the 360+ using the 'save to disk' option with no trouble.
Let me know if there are any other options/programs you would like me to test out.