Hi Angela
As I don't know which Hobby caravan you are looking at I can only pass on our knowledge of these vans.
Firstly, you should ensure that the Hobby you are considering is legally towable in the UK (anything wider than 7'6" forget). Some Hobby caravans are too wide and require a 3.5 tonne truck to pull them. They are also very much liked by the travelling fraternity so extra security device(s) should be installed (ie a 'Mule' - which is a fifth leg operated from inside the caravan).
Having been a previous owner of one of these large TA vans, end bedroom with walk round 'Queen' bed, etc., etc., I can honestly say they are great value for money. However, as your friend has already pointed out, not all sites welcome them.
Our van was located on a seasonal pitch and when we came to change sites to be nearer home it was impossible. Having rang around a dozen sites nobody would have a Hobby on their site, even with all the insurance and extra security. The reason given by a couple of the sites was: "If they can't take yours then they'll take another onw nearby. They won't leave empty handed.". Another said the police had actually advised them against entertaining any type of Hobby van!
Insurance can be another problem. We rang around a great number of insurance companies (including the CC) and they just weren't interested. We did finally get it insured with the NFU which we found to be very good. However, they did say that had we not had the 'Mule' fitted (the only company who at that time actually knew what it was) they would have had to discuss it with their underwriters! My advice is to ring around insurance companies and see if they are willing to insure the caravan of your choice and how much it will cost for the cover.
Ann