I have a beach, owned for a little over a year now. We are still learning about it but have not regretted it. It actually cost more a month than my mortgage and I was really unsure if it was but I am glad I did for many reasons.
Cost:
Firstly the residuals on a van like this are pretty amazing, you won't get much slower depreciation other than with some ultra rare vehicle. I feel safe that if I needed to, I could sell it quickly and without much trouble.
Uses:
We have 2 medium sized dogs and like camping. I use it as a daily driver, its my car for work and fits in most car parks without 2m or lower height restrictions.
We have used it to move furniture (I'm not so keen on this because the van is my precious), transported kayaks and bikes.
We've gone for days out and long dog walks and of course full 2 week holidays.
Its been a mobile makeup station for photoshoots and with the addition of the heater is an all weather adventure station..
Camping:
When we camp, we tend to sleep in the roof now but we have slept downstairs. There isn't really enough floor space for the dogs to sleep on the floor with the lower bed out (because we have a waeco fridge) but the full width bed has enough room for us and our two spaniels. If you have really big dogs it will be more of a challenge perhaps but is useable.
One of the upsides of the beach is that huge full width bed and more living space but this is also a downside potentially no cooking facilities etc. It has taken us quite a while to work this part out, but decision was easier because we didnt want to cook in the van anyway. Eventually I will get a slidepod I believe.
There are loads of threads on this stuff in more detail worth having a look around.