Does anyone prefer one over the other for moving baits? One over the other for weightless plastics? Does one offer better slack line sensitivity or less stretch than the other? 

I actually prefer sunline reaction for moving baits with terble hooks. I havent found anything wrong with it. Plus...its blue. 

I only use sniper in 10-14# test for senkos/light tube texas rigged/light worms. No issues. Theres a hair more stretch than shooter but its not going to ruin your day. Anything 16-20# for flipping and pitching jigs i use shooter or tatsu. 

Tried assassin. Wasnt impressed enough not to spend the extra few dollars on sniper. It was okay. Reminded me of a better red label .Sniper just works. Its proven and never faults. No reason to stray.

I was thinking more along the lines of single hook moving baits. I use Defier for trebles. Did you use the Assassin enough to determine if it handled better or worse than Sniper and compare stretch properties? 

Sniper handles better. I use(d) KVD on both and sniper still handles better. Assassin wasnt bad but wasnt great either. I use red label on my spinnerbait/chatterbait rod due to how much i change baits and retie and dont have any issues with memory or stretch. In 12-15#. To me, there wasnt a 10$ difference between assassin and red label so i didnt see a need to purchase it again. Stretch wise its a toss up in the mid# tests in my experience. it's just your average fluoro. Nothing impressive that sticks out that would make me choose it again vs others in its price.  It was't bad but for theres zero reason to not choose sniper for 3$ more vs 25 more yards. 

OP, Iabass might disagree with me but 8-12lb Assassin for Jerkbaits! OMG!!! It's like PB N J! As far as Sniper goes, I would put my money on Sniper all day for just about any technique. Only 3 things I use Shooter on are: C Rig main line it's stronger on the business end with the big weight slamming against the bead and swivel, paddle tails as my method of fishing these is dragging them across the bottom, and finally heavy cover flipping in clear water. 

IA I grabbed a spool of Sunlines budget stuff in 10lb to tryout, haven't really thrown it yet but as time progresses I'll keep you posted. So far seems better than Red Label. But haven't really gotten snagged or hooked into anything big yet with it. And I'm dying to try reaction for squarebills, super Nat has performed so well haven't seen the need to splurge. 

 

Sunlines diagram shows Assassin a hair more sensitive, not as good of knot strength, same on abrasion resistance, not quite as slick or supple, and a hair more stretch than Sniper. Think I'll use the Assassin on my paddle tail rig, and the Sniper on my Flick Shake set up. I love Tatsu, but I just don't feel like spending the money right now. 

For moving baits Assassin is fine. I don't think it handles quite as well as Sniper ,but I've used it a bunch on my spinnerbait ,squarebill ,and diving bait rods and have no complaints.

 Personally, I never use and kind of conditioner or spray. As was said, its less expensive that sniper and the spool is 25 yds. larger.

Thanks guys. Just gonna stick with Sniper for now. I ordered a spool of the green Sniper for the heck of it. Plus this way eventually I'll likely end up getting confused as to which reels I have spooled with Sniper, and which I have spooled with Defier! 

Green sniper is definitely cool. Good choice any which way you went. 

Eh I haven't found anything wrong with Sniper so thats what I use. I have two 2 bulk spools of 16lb which I use for everything but jerkbaits and deep diving cranks, for those I use 12lb Sniper