The drop between the most humble natural gut and the best plastic substitutes is a large one, in my view. Many multi-filaments try so hard to be "soft" that they end up mushy. NRG2 and NXT come to mind. The "better" multi-filaments I have tried were also not as durable as natural gut. As a final insult, some cost nearly as much as gut and more than a gut hybrid.
One multi that seemed headed in the right direction has gotten very little notice and is priced relatively low for a fancy string: Gamma Revelation Live Wire -- $7.25 at TW. I don't know about its durability, but freshly strung, I could live with it.