For what is unashamedly a cut-price camera the Z33 actually performs amazingly well. It starts up in a very respectable 1.6 seconds, and shuts down again in a little over two seconds. In single shot mode it has a shot-to-shot time of 2.2 seconds, while in continuous shooting mode it can maintain a surprisingly fast 1.3 frames a second apparently indefinitely. There are many more expensive cameras that can't match this performance.
Casio's autofocus system has often been praised for its speed and accuracy, with even mid-range models like the EX-S12 handily out-performing high-end premium compacts such as Canon's IXUS range or Panasonic's FX series. The EX-Z33 benefits from the same technology, with an excellent nine-point autofocus system which in good light is as fast and accurate as anything on the market. However the Z33 has no AF assist lamp and its low-light focusing is very poor, an unfortunate handicap for a camera likely to be used primarily for social snapshots by semi-nocturnal teenagers.
Of course when a camera is this cheap a few corners will have been cut in its design, and unfortunately for the Z33 one of those cuts has gone right through the middle of image quality. It has a slow f/3.1 - 5.6 lens with a focal length of 3.18 - 18.9mm, equivalent to 36 - 108mm. At wide angle it suffers from egregious barrel distortion and chromatic aberration, while at telephoto length it loses contrast, with the images looking washed out and hazy. Add to this the very poor noise reduction and the phone-camera quality image processing and the result is very disappointing.
For a cheap budget compact the Casio Exilim EX-Z33 offers decent build quality, simplicity of use and surprisingly good performance, but its very poor low light focusing and disappointing image quality are serious handicaps. Better to save up a few more pounds and get something a bit more capable.