Summary: With sub-$100 cameras, you expect some drawbacks. That's why they are priced where they are.
I found in my Canon PowerShot A800 review that this model definitely has some drawbacks, primarily that its autofocus and response times are very slow. Shot to shot delays are especially bothersome, as you'll see the "busy" message appear on the LCD screen between shots for far too long.
Even though the autofocus is slow, it is pretty sharp.
Pros: Inexpensive camera, Completely automatic, very easy to use, Uses AA batteries, which is handy when traveling, Autofocus is sharp most of the time
Cons: A800 has slow response times, even for a budget-priced camera, Colors seem to be dull, especially with indoor photos, Camera body seems a bit chunky, Zoom lens creates some noise and moves in a jerky motion, Autofocus is slow, especially in low light, so you'll want to pre-focus by pressing shutter halfway