First I have owned and used a lot of BlackBerrys. I started with the 7100, and have moved up from there to use the 8700, 8800, 8100, 8300, 8310, 8320, and now my 8900. I have also used a Storm 1 some as well.
The 8900 is an amazing phone. Its fast and snappy. I don’t have the constant problem of running low on memory I had with my 8320. The WiFi is great when I am somewhere with weak signal, or best of all on an airplane equipped with WiFi. I was able to surf, IM, and Tweet the entire flight. I have never had a flight feel so short.
The phone is a nice size to fit in my hand for typing or calling. The keypad is great and I have no issues typing on it.
The only complaint I have in the design is the placement of the charging port. It is a little inconvenient to hold and charge, but you learn to work around it.
I have no complaint about the memory card slot being under the battery. I don’t have a need to change it.
By far this is my favorite BlackBerry I have used and would recommend it. It works perfect for heavy email, texting, and messaging that I do.