Why would I want to use this material over a standard tying thread? From what I can gather, it has great strength, but what other benefits does it have? It appears to cost a bit more than standard Uni or other tying thread.

It is particularly good for tying glo-bugs, regardless if you use mcflyfoam or glo bug yarn. It allows you to have a ton of thread strength with minimal build up. If you can find a brown version, I like using it on bead head flies, where after you whip finish you can tighten up the thread and sink under the bead, and you will eliminate the (ugly) thread collar.

Its ultra slippery and is awsome for spinning hair. You can cut most most tying materials if ya hork on it too much.

relative best strenght to dia ratio ive used the stuff its nice but you can get away with a regular 3/0 or large thread for most of the stuff you would use this stuff for . does work really nice for eggs especially tying them craven style (a lot more wasteful but really fast )

It's strong as hell. Great for spinning hair and making globugs.

Also, don't use GSP with ceramic bobbins. The thread will chew up the ceramic insert.

Thanks for the replies fellas. I'm pretty clear on its use and applications, none of which really apply to what I'm doing. I'm looking to tie some sculpin patters (which don't have spun deer hair) and the recipe called for GSP tying thread. I think I'll just use 3/0 and call it a day!