We used the plastic picnic benches with stools attached when the kids were smaller, progressed to an aluminium one thinking it would be a bit more sturdy, then bought a table and separate chairs which fold up small and are lightweight (Lafuma CNO).
Our table has a solid top and legs which are adjustable, which is useful on uneven ground. I would personally go for the sturdiest table which is quickest and easiest to put up and without gimmicks such as undertable nets etc (we tried the slat top ones and they drove us nuts!).
If you are a Costco member or live near a costco I strongly advise purchasing one of their folding occasional tables (designed for using when you have gusts etc. and can't fit everyone round the table).
The costco tables are very very sturdy and well built, far better than any camping table I have seen. They are also very large and would easily accommodate all your family. We had 5 adults and two kids round it for a meal in my tent last week!
Only downside is they are quite heavy but if you have a trailer you are laughing.
The smallest packed size aluminium table with benches is the Coleman Pack Away. The table is a roll-up design which fits inside the benches, so the packed unit is half the size of the picnic tables that fold into the table. You could sit additional adults on stools / chairs at the ends if you want to sit 5 / 6.
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.