Poly vs. Steel Blazer Tank?

[muddpile]

I am going to be purchasing a rear tank kit this week, and I see they offer a poly and a steel. Why are there two different options (same price) and which one is "better". Is there a reason for using one or the other? Also, who has the best deal on one with the straps and sending unit right now? The shipping is going to kill me regardless, so I might as well pinch my pennies.... I have an Athey's catalog that has it listed at $235, but I don't know how current it is.

Thanks!