Hal once bubbled...
Two that look good in moderate price range are the Aeris Atmos 2 and the Suunto Vyper. The vyper claims to have reduced gradient bubble model. Don't know whether the Aeris has something similar. Dose either or both adjust automatically for altitude? Any thoughts on these? Other recommendations?
Both adjust for altitude automatically. Both are good computers.
There are some differences between them which might make one or the other better suited for your style of diving.
The Suunto computers emulate RGBM by adjusting internal constants of a Haldanian algorithm according to past dive history. Rapid ascents, reverse profile, repeated up and down yo-yo profiles are among the things the Suuntos will detect and will cause them to reduce the NDL limits for future dives up to 100 hours later. If you are an occasional diver and not really aware of your profile, this can be a great assist in ensuring your safety.
Atmos 2, like the many other computers made by the Oceanic subsidiary Pelagic Pressure Systems, is a rather straightforward N2 tracking system that simply monitors N2 loading using a Haldanian algorithm very similar to that of Suunto, but without the adjustments of the NDLs in response to diver misbehavior.
If you simply want the computer to do some detailed tracking and accounting of N2 levels then the Atmos 2 is better.
It also has a much, much better display of N2 levels. The N2 bargraph is a reflection of N2 loading as a percentage from sea level saturation up to NDL limit. In other words, the bargraph display is similar to a graphical display of your current "pressure group" of a table system.
This differs from the Suunto bargraph, which is simply a graphical display of NDL time. On a Suunto, even if you are heavily loaded, once you go shallow and NDL is a long time, the bargraph way into the green. On the Atmos the bargraph will properly display true N2 loading, and will slowly recede only as you offgas.
