Korkers makes quite a few boots, at varying levels of price and performance/durability. Some are better than others, though the top end ones are a bit pricey imo. The interchangeable soles I think are a great concept, and I take advantage of that to some degree. I have bought 4 pairs so far, and bought my wife a few pairs; so I think that's an overall endorsement. There are a few negatives in my mind which I do hope to see improvements on (they do seem to be making steady improvements with each season):
-the overall durability is a bit less than I would like, for the top end boots especially. I had a pair of the "Redsides" which were the least durable, though for $100 I thought it was about what is fair to expect.
-I am not a big fan of the BOA type lacing; while it is convenient when working properly, they are too prone to issues for me. Sand/grit will work it's way into the ratchet at some point and needs to be cleaned (frequently ime). Then there is the random accidental release, which I've only had once but my wife has happen at least a half dozen times. I pretty much only buy their regular lace boots now.
-I don't like that the two standard soles included with the boots are the two that I am least likely to use, particularly the "sticky rubber" (non studded). Between my wife's boots and my boots, we have a pile of the non studded "sticky rubber" (an ironic misnomer if there ever was). Landfill material, and added cost to to the product. I like that you can purchase the soles independently, wish that you could also purchase the boots with or without soles (or with the sole of your choosing).
-I have had ZERO issues with the soles coming undone ... when the boots were intact. Unfortunately, they depend heavily on a tab on the back of the boot which can (and usually does) come off pretty easily. You really need to baby this attachment, and in the donning and removal of soles it's easy to put a fair bit of torque on this fragile tab if you're not careful.
In short, I think they have a "good" product; not perfect, but very functional and enjoyable to use. Fit and performance is great, the "bang for your buck" I think is reasonable, though I would be a bit hesitant to spend the extra money on the higher end boots they make as I don't think the longevity is quite in line with the added cost. Yes they probably will hold up better than their low cost boots, but not much better (in my experience anyways).
HTH,
JB