I bought a new combo, 6'6" Med casting fast action, that I really am liking for spinnerbaits, and it feels perfect for hard jerkbaits.  I have 12lb Ultra Soft on it right now.

Do you think I should switch over to 20lb braid?  More sensitivity for the slack-line presentations...

I have been using the Ultra Soft 12lbs on my bc for jerk baits and have had no problems.

Later,

I have been using the Ultra Soft 12lbs on my bc for jerk baits and have had no problems.

Later,

Me, too!

8-)

I have been using braid with a fluro leader for my jerkbaits the last year or so and the sensitivity is unbelievable.  I had to switch jerkbait rods though since the rod I was using was too stiff and I was losing more fish than I thought I should.  Now with a rod with a much softer tip, I believe I catch far more fish on jerkbaits with the braid then I ever did with mono or straight fluro.  

Most of my hard jerkbait fishing is done on the river for smallies. Due to the walleye and musky, I've been using 20# Suffix Performance braid (on spinning tackle) with no problems. I do have a baitcasting set up that I used (rarely) for largemouths. That's spooled with 14# Suffix Seige.

Do you think I should switch over to 20lb braid? More sensitivity for the slack-line presentations...

Yes. It's much better for aggressive retrieves, and at least as good for slower retrieves. You simply have more options with braid, as far as retrieval versatility. Any little twitch of the rod transfers to the lure. With non-braid lines there's a bit of a lag, which may be good sometimes. However, you can also simulate that lag if you use braid.

I use a flouro leader - it seems the hooks will foul much less on the cast with a flouro leader.