To the front of the smartphone is not different from the original myTouch 4G, except the sliding keyboard, the back of the device is now home to an 8 megapixel camera units (1080p video recording is very likely to be available) with auto focus - which is an upgrade from the original myTouch 5MP camera.
We already know that T-Mobile Slide myTouch 4G will be launched with Android Gingerbread, wearing a slightly modified version of the HTC Sense 3.0. Reportedly, this device has a fast performance but no definitive information on the CPU (it might, 1.2GHz dual-core processors like the HTC Sensation).