I agree, buy one and your smoking almost right away. Build one, well you get the idea. You are not going to build one in a day or 2. However, if you build one, you can build it to suit your needs, plus it's fun
I built my reverse flow, took about a week, and several smokes to see where improvement was needed. Now I am in the works of doing a stumps clone on an old enamel interior refrigerator. This one will be mostly used for sausage.
Then there is option 3. Buy this one, turn out some good smokes, AND build one.