Tom......that's true, but most "recreational" computers are going to do the same thing, at least in my short bit of experience. I've run the SIMDIVE mode on my Vytec on back in June on a simulated deep dive on air and noted that the first stop was in the 50ft range, with most of the time spent at 25 and 15 feet.
And I do agree with you that for the dives that you tell us you're doing, planning with a good deco planner that uses deeper stops, writing them on a slate, and then following them is definitely more conservative. But Scuba446 might not be ready to be diving at that level yet.
Scuba446...As far as recreational diving goes (not going beyond NDL's, keeping relatively shallow, etc), the Vyper is one of the best computers out there. I am currently on the Vytec (the bigger brother of the Vyper, but very similar) and I like it very much.
* Fits well on my wrist
* Large easy to read numbers
* Information laid out in such a manner that a glance gives you the detail you want
* Factory settings make its conservativeness to fit my current "zone"
* User settings allow you to increase the conservatism when you encounter conditions beyond that of an "easy" dive like heavy current. (this is one of my favorite features)[/]
* Easy to access and use menu system to for the various features.
* Sturdy and well built.
Online prices less than $300 for the Vyper.
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(Just re-read your posting, "I am seeking something that will do deco")
Now I see where Tom's comments came from.
Ummm...well, then no computer might be the one that fits your criteria of "do deco and less than $500". The few that are known for best handling planned deco diving are easily $1000 and more (VR3, Nitek3, and Vytec). Usually because if you are doing planned deco diving, you are also managing multiple mixtures of EAN. And if you want your computer to calculate your N2 and O2 intake correctly, they have to be capable of being told you switched to the different mix.
I guess for now, to meet your criteria, Tom's suggestion of the Vyper set to guage mode and strict use of tables is the best solution.