I have used the Analox, Vandagraph and Suunto O2 analysers.
Personally i didn't rate the Suunto, It never agrees with any other analyser and just feels cheap.
I used a Vandagraph for a long time and they are very good, reliable instruments.
I currently use an Analox and it is great, simple to use, has a readout freeze button, waterproof and robust.
As an instructor I can get the Analox O2EII cheaper than retail for students and I'm considering becomming a distributor so if there is some demand on here I will follow this up. Email me if you are interested.
mark@dive-tech.co.uk