How about that it worked for me too... It broke the conversation app and the GSM data monitor tool(this is likely due to the new home network data counter not GSM in the phone options, Nokia this is a stupid change I don't want to keep track of home internet use combined with GSM)... Please tell me if this is a one off...
The refinements are worth it though with the online accounts seeming to work a heap better, as in logging in every time...
I can confirm it did kept all my contacts, messages and data such as photos...

I used a Virtual 32 bit XP as Vista 64 had trouble and used the command:
flasher-3.5 -F RX-51_2009SE_10.2010.12-9_PR_C
OMBINED_MR0_ARM.bin -f -R

So calls work, conversations work, email works, all the basics so far... Maps is a little different, still crap(ie. no voice guidance)... but search results are a little better...

So if you really feel like an update give it a go... It won't kill you! it will break a few apps though...

But all in all at the end of the day what is the update with out it's Qt apps from the store??? It holds nothing against android or apple. We don't even have a thousand useless apps...

Choice is worth nothing if you have nothing to choose...

Just my 3 fity...