I bought this set a few years back and am just now replacing it.  I give this 5 stars for the price, 3 stars for the quality.  Overall, a good deal if you only do light traveling and only expect this to last a few years. Here is my experience with the set:

Large Bag - One of the wheels busted after the second trip. The bag was fully loaded, and the short plastic piece that ran through the center of the wheel snapped.  The second wheel lasted about 2 more trips before the same thing happened.  Both are still usable, they just don't spin well... This is really the only reason I did not give this set 5 stars. It's a pain dragging the large bag around with wheels that barely turn.

Middle Bag - Still going strong.  I don't use this one much though.

Carry-on (21" bag) - My most used bag.  After about 20 flights the back of the bag is starting to separate from side walls.  The stitching is just coming apart.

Smallest Bag - Still one of my favorites for overnight stays.  There is no plastic on it to break and it's very durable.

So, yeah, the bags won't last forever, but you're buying a full set for less than $100.  I wanted to replace these with some nice, high end brands, but the reviews on those are about the same.  Zippers break, fabric rips and tears. Quality is always an issue no matter what you pay... so stick with a cheap set and just plan to replace it after awhile.

Summary:

PROS:
- Great price
- The fabric is very durable.

CONS:
- Construction on the wheels is very cheap and lacking in structural integrity.

All in, a good purchase.