I found that with my eldest son, nephew and a friend's son that pull ups were just used as nappies and didn't encourage training at all. To me they are just expensive nappies with no real training purpose. I just used jocks with oddly enough panty liners in them if we went out.
they do the same job but can help feel when they are wet but absorb accidents and are a lot cheaper than pull ups.
Good Luck!