We've used deps on a number of occasions and I never really enjoy it. Even with our regular dep drummer (who was a session musician for many years, including Level 42 no less!), it's a little nerve wracking as it never feels quite as natural. However, we never want to cancel a gig so we make sure we're as prepared as possible. We've had a couple of just show-and-go deps which is tough but we've rarely had an audience been upset about it as we do our very best to keep it tight and play our socks off no matter what. So I'd say it's worth going for but be prepared to feel different and up your game to maintain standards - for example, with all our deps I tend to babysit closely and play the role of conductor. But we always feel good that the show still went on.