Back in the day, tables were the standard. Now, the majority of scuba divers dive with a personal dive computer and for good reason.
The computer calculates your depth, bottom time, ascent rate, and no-deco limits in the moment. Tables can't do best dive computers that. If you change depth partway through, the computer recalculates. Tables are set before you get in.
Watch-style computers are what the majority of divers buy these days. These are compact, readable underwater, and you can wear them as a regular watch as well. Console models are available but fewer people choose them these days.
Entry-level computers go for around $250-400 and cover everything most divers would need. They give you depth tracking, time, NDL, dive logging, and often an entry-level freediving mode. The $500-800 range gets you wireless air monitoring, improved readability, and extra nitrox compatibility.
What buyers forget is conservatism settings. Some algorithms are more conservative than others. A tighter computer gives you reduced bottom time. Looser algorithms allow longer time but with less buffer. Both work. It just what you're comfortable with and experience level.
Worth talking to people at a dive shop who uses multiple models before you decide. Good dive stores will have real-world feedback on what works and what isn't marketing. Most good dive stores have gear reviews and comparisons on their sites too