The Vyper is a good computer and it does the job, but as said above, the Apeks gives you the option of switching gas mixes underwater. Now you might not want to do that right now, but if you get into excellerated deco, etc, later on in your diving life, then you won't need to buy another computer if you get one that can handle it now.
Might be worth looking at Tusa's DC-Hunter IQ-700 it is identical to the Apeks, but in the UK it is cheaper, and comes with a protective screen.
Mark
The Uwatec mentioned above is a nice computer, but it is air-integrated via a transmitter and is in a completely different price bracket, so can't really be compared directly with the Vyper and the Quantum.
