I don't have too much experience with outdoor speakers. However, I have been looking into a speaker company recently that I had never heard of before. They are
The Speaker Company. A friend of mine just bought a 5.1 system from them for about $300, and I was really surprised at the quality, both aurally and build wise.
They offer outdoor speakers too. I don't know too much about them but they are only $70 a pair and would most likely outperform those Rat Shack speakers you mentioned.
-Brad