I'm currently living in my camper right now, 5 days a week. I've been doing this for a little over a year and it has been much better than I ever imagined. I've never owned an RV of any kind before and was concerned that my initial planning wouldn't work out.
I decided to do this as a result of a very unexpected new job. But I didn't want to sell our existing home and buy something new so I decided to look into an RV. I decided on a truck camper because I could get the features I wanted even if it was a little smaller than other options. It's only me in the camper during the week, my wife stays home.
That's the context to my situation, now the details.
Camper - I purchased a brand new Northstar 8.5 Adventurer. I chose Northstar because of their excellent reputation and the fact that I could work with and learn from Rex Willett. My camper has simply been perfect for my needs. It is fully optioned, cassette toilet, a/c w/strip heat, elec/gas hot water, solar, thermo pane windows, and dc refrigeration. Rex really knows his product and the many ways in which they're used. My camper has experienced a temperature range of 15-107F, heavy rain, small hail, and wind with no problems and all systems operational.
Truck - I already owned a 1996 3/4 ton Dodge long bed Cummins which was suitable for this camper. I installed Happijac tie downs and air bags on the rear end. Trucks like mine can be found on eBay for $10-12k. I get over 17 mpg with the camper but I don't leave the camper on the truck.
Parking - Here's where I'm a little different than some others. I stay in an RV storage facility where I'm plugged into a 30 amp service and have available water and sewer. I pay $150 per month for everything. The camper simply stands on it's 4 jacks. I'm inside a gated yard with security cameras. It's not a green grassy yard with trees but an asphalt parking lot. Not fancy but very functional and close to work. Apartment or house rents in my area are in the $750 per month range plus utilities. My calculations indicate that I'll recover the cost of my camper in about 2.5 years. This doesn't include any residual value which it should have and I'm hoping that it will last longer than 5 years! I don't have any other utility costs because I don't use much propane because I can heat and cook with electricity but I do keep both bottles full. I don't try to conserve water very carefully because I have a hose bib right behind the camper that I use to fill my fresh tank a couple of times per week. My cassette toilet lets me pull it out and roll it to the dump station so no sewer hookup needed. I actually was offered a free parking situation with all utilities but I decided against it because I didn't want to have any security responsibilities.
Downsides - Hmmmm......tough one. For me none but I find it amusing the reactions I get from people who learn about my living choice. Some are amused when I tell them I live in the back of my truck and some take a step back! Maybe not living in an active social area could be for someone but I'm an old guy and like a quiet surrounding. Probably the biggest issue for me is the minimal amount of hobby space. Just takes creative planning with road bicycles.
I'm not sure if my arrangements can be duplicated but I think it's possible. There is no doubt in my mind that I'm much more comfortable than the other living options. I also find it very economical for me. Good luck in your evaluation, I hope you find what you're looking for.
Dave