Carlos;
What Max meant was that most people here will choose the latter of his two options... That is, most people here decide to build their own projector. That means we buy our own lasers.
There are already several threads in the product review forum that talk about different brands of lasers, and the pros and cons of each one. I suggest you go to the product review forum and read some of the threads about Lasever, Laserwave, Viasho, and CNI lasers. Those are the most popular brands that people here have experience with.
Pay particular attention to the comments about some of the reseller companies as well, as they don't all have good reputations. (In particular, there are several comments about Extreme Lasers and Axiz lasers that you might find interesting.)
Adam