Here it is. The definative decision over which is better. I've been reasearching my booty off attempting to discover the differences. Here's what I have so far:
Better with images/games
Buil in WIFI
That's the features thst stand out the most with me. Other than that, 2215 comes with Nevo while the 4155 doesn't. So, it basically boils down to WIFI and the CF slot. Since I want WIFI, the 4155 leads with it built in. But, since I want a CF slot for future addons, the 2215 leads because of the CF slot which can house WIFI and GPS and Cameras and whatnot.
So, I think I'm going with the 2215 because of the CF slot and a bit better on games/multimedia. The CF slot I know I will use later and the WIFI I won't use all the time so I don't need it built in.
What do you all think? Before Midnight tonight I'm ordering one from Newegg. So, these are the final hours.
The 4xxx series iPAQs are great PDAs if they fit your needs. Personally, I like to have a CF slot, not only because I need to test GPS a lot, but also it's very versatile when it comes to other accessories such as Presentation VGA cards, large and speedy storage cards for videos and gaming...