I must admit i had a different philosophy when we purchased our mobile. We looked at both normal and DG&CH units, but as the site was only open March to November we just went with a standard model as let's be honest - if it's -2C on the west coast of Scotland in March, i wouldn't be going down to sit in a caravan anyway, i'd just stay at home!!!
Having experienced it for two years now, i'm glad we did as during the summer we seem to spend more time chasing the heat out of the caravan with the windows and doors open. It's like a wee oven, and that's in Scotland ... i dread to think what it would be like with DG!!!! Even during last years pretty poor summer, it was still nice and cosy
I'm hoping for a better summer this year though, as i've decided to spend some cash on the house this year and we'll have three weeks at the caravan ... so fingers crossed!