As a contractor, I use a lot of ladders.
COSCO was the first to clone the Little Giant Ladder about five years ago. Apparently, Little Giant's patent was still in force for the hinges. I own the COSCO 17FT Worlds Greatest Ladder and used it for a couple of years, but I needed something longer. The only flaw in the COSCO are the angular steel braces on the inside of the ends of the center hinged section. These are a bit annoying, when you are using it as an extension ladder.
In January 2002, I purchased the Type 1 22 FT Little Giant from Amazon.com. The only difference was the hinges and a few annoying braces in the climbing area of the two narrow extension pieces of the COSCO. The COSCO is made in Korea. The Little Giant is made in USA. Both functions flawlessly to this day.
I found the Little Giant cloned at Home Depot as the Gorrilla Brand ladder at Home Depot. $99 for the 13 ft model and $199 for a 21 ft model. The ladder is essentially a China made copy of the Type 1A Little Giant.
My last purchase is the MT-13 Werner. It appears to be another clone of the Little Giant Type 1A, also made in China, probably by the same company that makes the Gorilla.
I would recommend the MT-13 and the MT-17 in the Werner Brand, but I still prefer the Little Giant in the 22 ft model. It is a lighter by five pounds than the 22ft Werner but cost about $130 more.
Since all of the original Little Giant patents have expired, the hinges on the Gorilla and Werner models are identical to the Little Giant.
Of all of the models, the MT-17 would be ideal for most home owners. It will go to the second floor window of a two story house. The 22ft model will go to the roof of a two story house, but only for one with a slab foundation, not one with a basement or a crawl space.
The 17 FT model is a good balance between weight size and function. The best deal would be the Werner MT-17. The quality of materials and assembly of all the models appear nearly equal.
One reviewer noted that these ladders were hard to extend. The best method is still the method of extending the ladder using the procedure described in the Little Giant Instructional Video. Since the methods are copyrighted by Little Giant, the clone manufacturers cannot use them with their own instructions sheets, videos or manuals. Accordingly, I cannot include the Little Giant Procedure in this review.
The 13ft. (Actual length is 11ft. 13ft is an OSHA rating, since extension ladders have overlaps.) ladder is ideal for a one story house on a slab or a trailer. When I first used it to get on a roof of such as house, I thought it was a little short. However, after using it several times, I found that it was ideal. The key is to place the space between the top and the second rung at the edge of the roof. I know that ladder makers recommend a grabbing length of three feet above the roof edge, but you would have to go around the side of the ladder's length above the roof. This "grabbing length" is a little arkward to me. Since the top of this and other Little Giant clones have flared tops, I prefer my method. I can stoop dowm and climb directly onto the roof, while keeping my center of gravity very low. The same can be done, while getting off of the roof. So the 13ft. ladder is just right. The thing I really like about this length is easy handling. It balances well, when fully extended and makes a compact package that fits nicely into a car trunk of even some compact car. In the step ladder mode, it is probably the sturdiest and safest that you could ask for.
For the price, the Werner MT's are the best deal. Best of all, the MT-13 is only $99 at Lowes.