It was surprisingly good, the girls loved it. All very happy with their bears and outfits, 'the best party ever' I was told. It is good quality stuff (but expensive, pants or shoes are a fiver!). The staff made a real effort with the party too and the children seemed very happy and not overwhelmed.
My tips are:
Go early, we did and they had the shop to themselves. The shop is heaving from midday onwards and parties at that time feel crowded and less special.
The staff are also more enthusiastic earlier (can't imagine how they must feel after 8 parties).
Have fewer kids and a bigger budget per head, we had 6 children. The children who bought a mid priced bear were able to get a full outfit with it. Last time we were there we witnessed a party for 20 children at £30 per head though (money no object for that family).
You can book a mascot for £20. We had a bunny 'Pawlette' who was very good and the children loved it. i thought it would be a waste of money but it wasn't.
Be prepared to cry as you hand over the money at the end. The damn bears came out better dressed than us!