I have tried black mamba gear twisted, penta, dynasty control, premium gut, black ion roughand am getting more and this is what I think of them.
BLACK MAMBA GEAR TWISTED- Pretty soft for a poly. Generates great spin and feels almost exactly like black widow
BLACK MAMBA PENTA TWISTED- A little on the stiffer side. A little more spin than gear twisted. Feels similar to barbed wire.
BLACK ION ROUGH- This is a really nice string. Feels almost exactly like RPM Blast ,but it gets more spin. At first it sort of seems to get a little side spin because of the way it is textured. Great string.
PREMIUM GUT- Good string. Similar to most sheep gut, but just a lot cheaper. Price vs. Performance is great
Other than that, they have fast shipping and the best customer service that I haver seen. And of course there prices are the best.