The trains aren't bad. They're not great, but they're not as utterly terrible as some people make out. I commute to Manchester three times a week typically and it takes ~30 mins on the train, I always get a seat and I've never been delayed more than 15 mins. At rush hour it would take an hour to drive and even an on-the-day return is cheaper than parking.

Edit to add: I go to London a couple of times a month. Not had a significant issue in years.