The dive computer is a part of the basic scuba setup. Since the first dive computer was introduced in 1983, a lot is changed.
When I started diving in the middle of the 1990s, we used dive tables and I bought my first dive computer in 1997. What a luxury was that was, just jump in the water and you knew exactly what your remaining bottom time was. The time I spent with dive table calculations for multiple dives a day was over. There was one other big advantage of using the dive computer – we could dive much longer now. The dive tables were not designed for multi-level dive planning but the dive computer was.
20 years later, the dive computer is much more than just a multi-level, non-deco, bottom time calculator. Now, all computers are "decompression" computers, so when you exceed the maximum bottom time, it tells you exactly which depth you have to accent to and for how long. Most computers can switch between two different gasses (Air and Enriched Air Nitrox), and even the more expensive ones can also switch between different gasses during the dive.
When you have a tech dive computer, you also can adjust the dive algorithm. Some dive computers have a built-in compass, is air integrated with a sensor, bright colourful display, wireless charging and titanium housing – these are just some of the futures.
Year after year I am diving with an Alladin Pro, the grey one. I bought my first Suunto, a D6, in 2014 because it looked cool and many of my friends used one and now I'm using the Shearwater Teric since 2022. As written before, all dive computers do what they have to do as long you dive in the limits of recreational diving.
Nowadays, most computers are for air and Enriched Air Nitrox (EAN). The computer lets you know what your remain bottom time is, tell you what to do when you exceed the maximum bottom time, gives you a warning when your accents speed is too fast, what more do you need? The choice is more based on how the computer looks, how easy you can read the numbers in the display, how easy you can change settings and use the menu. User comfort is the most important reason when considering what kind of a computer the diver will buy.
My advice: any Air/Nitrox deco computer as long you can clearly read the display and you understand how to adjust the settings.
My computer: Shearwater Teric