When it comes to soft plastic lures, straight tails do it for me

[SenkoSam]

The first soft plastic lure I caught fish on was a yellow 4" yellow Mr. Twister curl tail grub. Man did it catch smallmouth bass in a local river!
I figured I'd stay with the curl tail for largemouth and Texas rigged 6" Phenom curl tail worms. Again, a great design for a small lure. But then Uncle Josh sold various shapes of pork rind used as skirted jig trailers. That blew away plastic worms for a bit until other plastic shapes came out. 

Looking back, all soft plastic lure designs in the past had their moments - some better than others. As those designs became less available either because of lack of sales or they were replaced by the latest advertised wonder-lure sold, I've had a chance to look back and compare what I use today with what I caught fish on back then. Most obvious is my use of soft plastic lures that are straight from body to tail.
Even Uncle Josh's pork frog had straight triangle shapes tails. Senkos are straight from end to end. Most soft plastic designs I've come up with are straight. Sometimes I'll cast a curl tail lure, but far less of the time.

I could give possible reasons they do better than curl tail lures but suffice to say, as long as fish bite them, I'll cast them. Here are examples, some of which were shown in other posts:
cone tail grub:


Thin tail grub:


Joker Tail grub


Claw grub

Note: the one on the right resembles Uncle Josh pork frog trailer.

One of the best plastic worms I've ever used I the Yamamoto Kut Tail worm:

It has a unique action no other plastic worm has.

Fused grub bodies:


These and others are what I catch the majority of fish with and all are straight rigged on light jigs - all have different actions fish repond to.

[SenkoSam]

When it comes to curl tails, the lures always moves slower whether on a horizontal retrieve or on the drop due to tail friction with water. No action can be imparted to it. But curl tail grubs do have uses:
In current (river or stream), the lure moves with the current and its speed increased with or against the current with the rod tip - something smallmouth bass appreciate.

When used with a spinning blade (crappie spin), the thumping blade and wagging tail combination put out the most vibration of any soft plastic lure that fish also respond to. 

Lastly, wide-tail grubs (i.e. Kalin grubs) also put out large vibrations with their slower back & forth wag that bass find annoying enough to strike.