Visited here on a Sunday in October. It wasn't overly busy, although I had been expecting it would be.
On arrival, the staff advised us to start on Level 4 and work our way down and this was excellent advice. In fact, all 3 of our kids (12, 10 and 6) enjoyed Level 4 the most, so we spent the majority of our time here.
The Dragon exhibit (temporary) mostly consisted of a few dragon figures that move, but at 30 minute intervals, they bring out a dragon puppet which is very lifelike and the kids can pet, so that is a really nice touch.
The exhibits are very interactive, with lots to interest both children and adults. Mine in particular love the studio section, where they could record their own soundtracks, report the news, create a stop-animation sequence, appear in a dinosaur film and more.
There are also some great sections on building, electricity, nature and general science.
We had read on W5's website about their picnic areas, so we brought our own lunch with us, and there are plenty of places to stop and eat your food. There are also water stations where you can refill your water bottle. Toilets were clean and well kept.
We didn't eat in the cafe so can't comment on that.
We spent over 4 hours in total at W5 and would highly recommend it. There are a number of restaurants in the same complex if you need to fuel up before journeying home.