Choosing between them
The most useful question is how much time this session has. If it is short, or you want to be able to stop at any point, slots suit that better: each round is self-contained and you decide again every time whether there is another one.
If you can sit for a while and you enjoy watching a result happen in front of you, a live table gives you more of that. The trade is that the table sets the rhythm, not you.
Before you open the first game
Decide the amount you are willing to spend this session and the time you will stop. Both are easy decisions now and considerably harder mid-session. The full guidance is on the responsible gaming page.