Just as a counter-example, I purchased my Wisdom 2 in March of this year (2008) and have logged over 50 dives with it so far, max. 140'/typical 70', and have treated it fairly roughly with no problems.
A couple months ago, I did catch the fact that the quick release mounting to the computer was coming loose, and tightened it before anything bad happened. Also, one time I got these crazy pressure readings up and down so I thought it had busted, but it turns out it was my fault - my tank valve wasn't open all the way.
I know a lot of the Wisdom 1's had reliability problems initially, back in 2005. But I think they fixed those on subsequent manufacturing runs, and then rolled what they learned into the nearly identical-looking Wisdom 2, which has had a much better track record.
...which isn't to say there might still be some that fail occasionally out there. It's just a piece of electronic equipment after all. But I think the Wisdom 2 has a reliability as good as comparable units.
One problem I have heard about is people replacing just the battery, and either not replacing the battery compartment O-ring, or inadvertently removing or damaging it. Either of these could definitely cause the problems divingdeep described. I haven't had to replace my battery yet, but I did buy the official battery replacement kit (which includes a new O-ring) from my LDS to keep in my save-a-dive bag. The manual clearly states that when you change the battery, you should change the O-ring.
>*< Fritz