Upgraded my wife's laptop to LM9 RC over the weekend using the 64 bit version.
The minor problem (viewtopic.php?f=49&t=44748) I had with wireless drivers (network drops, spotty signal) using Helena have disappeared and LM9 works fine out of the box including the proprietary ATI video drivers.
Funnily enough, it's the minor things that make a big difference. For example, my wife likes 'Firefox' and 'Thunderbird' icons on her desktop which is now quickly done using right-click 'Add to desktop' whereas it was slightly more convoluted in LM8.
Nice to get Thunderbird 3 too and a wealth of choice in 'Software Manager'.
My only slight disappointment was the startup boot time which was supposed to be reduced. I see no difference (on two boxes) from LM8 - if anything I suspect it's slightly slower although stupidly I didn't take stopwatch timings to backup this claim.
Fantastic news that the i386 and AMD64 versions now ship simultaneously. Well done to all who made it possible.