I am biased as DH works at The Space Centre,but kids seem to love it.I am not interested in space at all,but still managed to spend hours looking around.I was surprised how interesting I found it.
The staff are great with kids,enthusiastic & really helpful.There are lots of interactive displays for the kids to play with too.
One word of warning though,the lift in the rocket tower is still not working,so lugging a pushchair/tired toddler up loads of flights of stairs is no joke.
HTH