If I can add anything to what Webby and sunsanvil have said, Scotch (and other brands) masking tape is not really so good for scale modeling use, right off the roll. As noted, it's far too tacky (too much adhesive) and it can pull off layers of paint. This sticky quality is a reason some guys use that masking tape to remove old decals when restoring/reworking old builds. If you do use it, I recommend sticking it to the back of your hand, or to your trouser leg, a couple of times, to remove some of the adhesive.
I used it exclusively, when I got back into building models, and learned through trial and error that it's not as good as purpose-made products from the model supply companies. But I was driven by my cheap, er, ah, thrifty nature, to find something that cost less than Tamiya tape, for the same foot length. I tried the blue painter's tape, which is a better alternative than tan masking tape, because it's got a much lower tackiness. It cuts relatively easily, too. But I found that for masking canopies, where crisp edges are needed, it has a tendency to tear and leave fuzzies. It also tends to leave its adhesive behind, requiring cleanup with an ammonia-based cleaner, like Windex.
I decided at that point to bite the bullet and spring for a roll of Tamiya tape. And I agree with the others, it's perfect, especially for masking canopies. It cuts beautifully, and it has just enough tackiness to stay put, yet it comes away clean.
I still use the blue tape for masking large areas, like wing or fuselage surfaces. But I use only Tamiya tape for masking clear parts, like canopies, or other jobs where intricate masking is required. That's my balance between quality of product and cost. The blue tape is cheaper, so I can go through it for large, general masking, and reserve the more expensive product for jobs where it works best.
Hope that helps you!