There's two routes to go to getting millions somewhat quickly, the free one and the premium one. House farming is better because it doesn't cost any real money, it earns a lot per day and you level up more frequently so you get more free donuts. I've seen a few people on my friends list who have nice house farms and not a sea of roofs, so it can be done nicely. However, I chose to go the premium route, and have never actually house farmed, except for a few browns and blues early on. I bought a ton of items with high bonuses. Going by the Gulp N Blow, my bonus is at 455% right now, so getting more than triple on every building and task can really add up if you play frequently enough and have all the buildings. I only have 18 houses total and very few duplicates, but manage to earn around 300K per day. Other than Magnifying Glass, I haven't spent much cash, so I'm making and saving almost 2 million a week, but it cost me a lot of donuts. That's why I think house farming is smarter, especially for players just starting out.