I bought a Veo 100 (wristmount) as a backup when my Uwatec was in the shop. It's very easy to operate and read, and it's about the least expensive I could find. If you want to dive air limits on nitrox and track your O2 exposure manually then that will work. If I could make only one recommendation it would be to get a wrist mount computer, it is much easier to read and follow your depths and NDL times compared to looking at a console. You can then get a wrist mount compass for the other arm, and a small SPG. Even if you get an air integrated computer later, you'll keep the SPG attached as a backup.