I bought this console about a year after my Original 360 RRoD'd just as the 3 year warranty ended. This console comes with everything the Original and Elite versions were missing, such as a much larger HDD, Inbuilt Wireless internet capabilities, more USB ports, (however the PS3 had most if not all of these things at launch.) and to a less important extent, touch sensitive power and eject buttons.
The biggest plus aside from the inbuilt wireless is the apparent (only time will tell) improved cooling system. Noise wise the console runs near silent upon start up. There is a slight increase when running a game from disc, but that is to be expected.
One thing I still find rather irksome, and Sony are also guilty of this, is no inclusion of any kind of HD cable with the console. All that comes in the box is your standard component cable. You would expect a HD console to have these as standard, but apparently the two companies are too tight fisted to do so. I would recommend, if you need to, ordering a HDMI cable at the same time as purchasing to avoid any hassle.
Overall, it's nothing spectacularly new, so don't expect to be blown away. The improvements are just what the 360 had been missing all along. I wouldn't recommend buying it if you already have a functioning 360, just wait until that one inevitably dies.