In the casinos, the house will normally try to seat you at their choice of tables. In the online world, the choice is all in your hands. Sites tend toward reputations. But, all of them can and do provide an unusual table.
You will often see more than one seat available. If you observe the table for a bit, you might see that one is far better than the other. In flop games that is particularly true but it also has some benefit in the ante games that vary the leading hand based on the exposed cards. It is still nice to be behind the loose cannon at least part of the time.
Different sites provide different amounts of information. All seem to give average hand values. If you are very comfortable with your game you might seek the action table. If you aren’t as comfortable with your game, you might want to hit the less aggressive table. Don’t take the average hand value as gospel. There may have been an unusual happening with overly large or small pots spiking the value.
The number of people seeing a flop or calling the door is a bit more reliable. Really tight tables aren’t that frequent but they do happen. Thieves will love such a table and the tight aggressive will see that it is less likely he’ll get paid off on his good hands. If you are seeing more multi-way pots, you’ll win more on your good hands.
The only way to really know is to observe for a bit. This is especially true in the single game setting. With my current favorite, HORSE, players bring a mix of skill and comfort to the various games. Original opinions watch one game can be skewed; but, it is still useful. This is a time you may want to pop up more than one table