Having one large room is not badass if you have no veg room, no nursery, no mom chamber, or no flower chamber, where do you get the plants that you WILL grow in the large room? How are you gonna veg your plants if the big room is in flower? Let's not get into what will happen to the entire crop of there is a parasite. There are better ways to spend your money.
Tents create negative pressure. This is key in keeping your smell under control as well as keeping parasites out. Building walls for your grow room used to be the way to do it, but we also used to use those loud magnetic ballasts too. Moving forward, the reflective abilities and the ability to segregate your plants with a tent far out way the benefits of the dust and crap from building walls. Basically, just don't get the most expensive tents you can find and spend the money you save on lights. Tents are the future, walls are the past.