Previously, I had a MT-F, whose battery cover was only to fix because of a fall with tape.
The new C4 I find visually and haptically much more pleasing. The keys have a better tactile feedback. Otherwise, there is unfortunately nothing new. Operation and functionality are identical to the previous 100%. Actually online reverse search would offer just when Fritz phone. Gets an unknown participants without suppressed number, the caller's name is in plain text on the display. A fine thing that I know from my Gigaset DX600 and appreciate. Instead, a Media Player and Internet Radio is built, the need yet but really no one ...
My wife thinks that the new device provides a better and clearer voice quality. I myself think that the new C4 slightly noisier. However, depends on who you call. I can live with that.
Unfortunately, the battery in the C4 keeps less long than in the MT-F. Even when not using the phone is the battery after allerspätenstens 3 days at the end, as I discovered after a weekend trip. The firmware is still not mature properly, because the same mistakes that I knew from the previous device, also occur here. It often takes a while until you can use the phone, when it "wakes up" from standby. Occasionally, the phone book is not accessible, and that I know scho from MT-F.
Bottom line makes the new phone a bad impression, but disappointed for missing changes. The review I am doing something difficult. 3 stars would be unfair compared to other phones. 4 stars are actually too much. Too bad that you can not differentiate accurately.