Back in the day, tables were the standard. Today, nearly all recreational divers dive with a wrist-mount computer and it makes sense.
A dive computer calculates depth, time, ascent rate, and no-decompression limits in the moment. Dive tables are a fixed calculation. If you go shallower mid-dive, it updates. Tables don't.
Watch-style computers are what most people go for at this point. They're small enough, easy to read, and you can use them as a watch as well. Hose-mounted models are still around but fewer buyers go that way these days.
Basic computers start around $250-400 and do everything the average diver would need. You get depth, bottom time, no-deco limits, a logbook, and often an entry-level freediving mode. Stepping up to mid-range includes wireless air monitoring, better displays, and more nitrox options.
The one thing buyers forget is algorithm differences. Some computers are more conservative than others. A cautious setting gives you shorter no-deco time. Looser settings extend time but at reduced margin. Neither is wrong. It comes down to your style and your diving background.
Check with the staff at a dive shop who uses a few different brands before buying. They'll give you a straight answer on what works versus more info what's just marketing. Most good dive stores put out product guides and honest reviews on their sites as well