Training with power and with a coach is especially beneficial if you have limited time.

Though I think CAT3 is where a lot of people like to be since the training needs and race demands don't take TOO much away from life. I know Waterrockets was talking about how he could easily get to the 2's, but the longer road races and increased requirement for training time would eat into his family time.

I can see that being a very real issue if you don't have time.

Hammertoe has also pointed out how training with a coach and power has really improved his performance with much less time spent training.

A coach and power meter might require money, but if you learn to coach yourself and buy a power meter you can good returns for your time if done right. The Allen/Coggan training with power is a great resource for this, as is Friel for general training.