Apologies for the obvious answer, but it really depends on how often and what you will use it for.
Having had caravan before you are a step ahead of newbies, but the biggest consideration is layout, especially in terms of a fixed bad which can mean a compromise on living space, especially in a small model, or having to make up a bed each night, or having a drop down bed.
We are on our second motorhome now, as opposed to a campervan, as we were in the very fortunate position of being able to get a decent part-ex price for our old one, and having some money available to make up the difference.
Its only the two of us, so ours is a 6m one, and we paid what is your budget for it.
We like going away for regular long weekends, and a week or two during the year, but tend to stay a couple of nights and move on. We have an awning that can go up and down in less than an hour so that gives us extra leisure room for not a lot of effort. We also try to find sites in easy reach of a walk, or short bus ride to local shops etc especially if away for more than 2 nights.
If you hire first, you may end up hiring 4 or 5 different styles before finding one you like, but there will be a compromise on anything you buy. On our new one, we went from a fixed bed, to a drop down bed, so the living area is bigger and more comfortable, but the compromise is losing cupboards and storage space, which we are trying to find solutions for, which I am sure we will get there.
We plan to keep ours long term, so happy to invest what we can into it, but I love the fact that most of our stuff is in it, and if we want to go away we just pack food and clothes, fill up with water and away we go.
We did toy with a caravan but it seems to me like a lot more time needed to set up, take down and so on (although I could be wrong), and neither of us really fancied towing, especially as the motorhome is so accessible to a lot of places.
If you are in no rush, its worth going to the Motorhome and Camping show at the Birmingham NEC in October (you have just missed the one at the start of this year), or one of the Warners shows as they have 100s you can walk round and look at, sit and see what you think.
I don't worry too much about the cost of fuel, as weekend trips are usually 1-2 hours drive away, so don't cost too much in the grand scheme of things. Insurance is about the same as our family car, although road tax is about £360 a year on our model.
It's not an easy decision and I would definitely think about an older, cheaper model at first to see if you enjoy it. You can easily make an older one feel more luxurious for not much money, and there are decent quality second hand ones about at the moment.