Ahhh, Korkers. I just received I think my 7th warrantied pair in 6-7 years. Good news is their warranty is pretty good. As long as you have not just sacked them out from regular use. Mine keep blowing apart after a year or so of use. Korkers keeps sending me a new pair, so I can't really complain. The interchangeable soles are pretty hard to beat. If it were not for this feature, I would not buy them.
My Simms G3 boots are in every way thinkable a superior boot to Korkers. Comfort and support mainly. The materials and construction difference is night and day, and they are not a lot more $ than Korkers. However, when the felt soles wear out, ya, a pain to deal with. When Express Reel was in biz he did a nice tidy job refelting, but his felt was not nearly as durable as the factory felt. I think the OE felt is a blend of real felt and resin or similar. Very durable and still quite grippy.
Anyway, by all means give Korkers a go, but there is a reason several shops no longer carry them. Nothing but warranty claims. I just deal with them directly and have not had any issue.
And if anyone has any advice on refelting Simms I'm all ears.