It has 2x the CPU power (the same as the iphone and Pre), 2x the DSP power, 3d video acceleration chip (the same as the iphone), 32 GB of ram expandable to 48GB, a 5.1 MP camera that can record 400x480 video, hardware keyboard (take that iphone), sim card slot, removable battery (ouch iphone), full flash support and copy and paste. The last two were below the belt. For physical size -
| n800 | n900 | iphone | |
| Length (mm) | 144 | 111 | 115 |
| Width (mm) | 75 | 60 | 62 |
| Thickness (mm) | 18 | 18 | 12 |
| Weight (g) | 206 | 181 | 130 |

Summary:
First, if you use From a specs standpoint the n900 meets or beats the iphone 3GS in every category but we've seen this before. The beauty of the Apple device is how well it works. It's a very solid device that just works. The issues have always been a draconian apps store policy, no copy/paste, poor camers, no flash support and a few other choices that Apples made that makes no sense. In the Apple world everything they say goes.
The disadvantage to the Maemo devices has been the immaturity of the software and not enough control over their apps. Ironically that's exactly the opposite of Apples main issues. Maemo has always been Nokia's red headed step child of an OS but it looks like they've swung the other direction and even though they're not admitting it they may have just put Linux as their #1 and Symbian as #2. I will predict (and you heard it here first) that Symbian will be phased out. Nokia isn't dumb (like Palm) and doesn't want to lose it's 50% of the Smartphone market because of an aging OS. Nokia's purchase of QT also means that the next version of Maemo will be moved to QT and the GTK (Hildon) will most likely be dropped.