There are good link builders out there they just charge a lot. Once you get a reputation for producing results you have more than enough work. I don't bother with companies that have low budgets or demand hundreds and thousands of links a month for there money. Real link building is slow going. A bad link builder can get you thousands of links and you won't move at all in the SERPS or sometimes fall backwards. A good link builder will get 20-40 links a month and you will move up in your rankings. It might take 3-6 months but you will move up and when you get their you won't bobble around like you will with bulk link building.
All this said there is room for bulk link building. As long as it is not a large percentage of your link profile. Don't let any one type of link dominate your backlinks.