I use u-bolt style jigs with worms & other soft plastics while smallie fishing. I like 'em, but I'm barely amatuer level so they might not be any better than a standard t-rigged bait. Truth is you can do essentially the same thing by pinning a worm weight on top of a snap and clipping on your hook of choice.
I'm with Darrell on the Wiggly Jiggly, it'd have to be a VERY soft plastic to make much difference the way those are designed