Review: Sony Ericsson C905a
Screen
The display on the C905a is fantastic. It is extremely bright and colorful. Images, icons and text all looked crisp and sharp, and I had no problems reading it outside at all. This is perhaps the C905a's best feature.
Signal
The C905a can connect to AT&T's HSDPA 3G network. In my time testing the phone in New York City and New Jersey, I found it was able to remain connected to the network most of the time. The only instances where I noticed "no signal" were in areas that legitimately had no signal, such as subway tunnels. How did this play out in real-world calling and data connections? The C905a didn't miss any calls while I had it, and experienced a slow data connection only once. Long story short: signal performance is good.
Sound
I was worried the first few times I made phone calls with the C905a. Sound in the earpiece was extremely distorted and garbled. Turns out, that's how the C905a will perform if you put the earpiece volume all the way up. If you lower the volume to something less than 80% strength, calls sound just fine. Even at 40% it is loud enough for most environments. I barely noticed any odd noises, hissing or other interference. The speakerphone was decent, too, though I wish the ringers were a little bit louder.
Battery
Battery performance was pretty good. I easily got 2.5 days out of the C905a consistently. The only thing I noticed that really killed off the battery was, er, well, taking a lot of pictures with the flash active. Bluetooth didn't seem to have an impact on battery life, nor did listening to music or even browsing the web. It was reliable at 2.5 days.