“3 Tab Shingles Advantages:
Three- Tab shingles have many advantages, however the primary reason they seem to be chosen is PRICE and price alone. They are certainly the value leader in the residential market. Thankfully they are still prevalent in most home centers and commercial roofing distributors. You can probably find just about any color family you need to fit your homes aesthetics. The most common 3-Tab shingles come in 25 and 30yr varieties, however you can find these in shed shingles rated to last down to 15 years or so.
3 Tab Shingles Disadvantages:
One of the primary disadvantages of three-tab shingles stems from the design. They lay so flat on the roof that any inconsistencies in the roof deck will show right through to your finished roof. For a long time they were the primary shingles installed on roofs in the United States but have more recently come out of favor in lieu of the introduction of dimensional’s. Longevity; the other Achilles heal of 3-Tabs, although they are rated for 25-30 years on average they only last 15-18 years. They do not have very high uplift ratings for wind and I can’t remember the last time an architect specked them out for a commercial product. Most all manufactures have reduced their product offerings in three tabs to 25 year or 30 year varieties and they do have somewhat less color options, however this shouldn’t be a problem for most. To find available 3-Tab shingles check out the Asphalt Shingle Comparison Chart. Although you can find the rare manufacturer that will put an algae resistance warranty on these type of shingles there are certainly better choices out there.”
Source: http://www.researchroofing.com/3-tab-shingles-advantages-disadvantages/