I have used the Air Z Nitrox for about 6 years now; I had the original model and now have the new model after the battery died in the original. The battery lasted for about 5 years (about 250 dives) I paid £110.00 for a battery replacement, which actually means you get a new computer.
Ive always been pleased with the Air Z Nitrox and have every confidence in it. It is easy to read and the accent rate as a percentage is extremely easy to read, I also dive with a suunto Stinger but prefer to use the Aladin as my primary computer. The Suunto computers are definitely more conservative especially after a short surface interval.
I will say you certainly need the memo mouse. The computer holds on two hours of dive profiles even though it stores nineteen dives in its memory, you also need the memo mouse to communicate from the PC to the Air Z to enable you to change the settings, I.E. turn the audible buzzer on and off, adjust the breathing rate alarm (this set at the manufacturers setting is quite annoying you really do have to turn this down).
The memo mouse has a serial connection instead of a USB, but this is not really a problem as most PCs still have at least one serial connection.
If you are considering getting the Aladin now you may consider the new Smart Tec coming out soon, this can use three nitrox mixes 21% - 100% with three transmitters.
100 hours of dive profile storage. The smart tec uses inferred communication so theres no need for a memo mouse.