I have been meaning to try K-97 but I haven't used it yet. I have a pack in my refrigerator so I should know more later this year.
WLP029 is a very good yeast and turns out fine. However I think I like the flavor from Wyeast 2565 a little better. The only trouble with 2565 is that it takes forever to clear, like 6 or 7 weeks. (WLP029 is totally different, and clears very fast in just a week or two.) If you want you can add gelatin at the end of fermentation to knock the yeast out of suspension, that's what I would do these days. Same story for Wyeast 1007, which I think would also make an excellent kolsch. I have only used 1007 for an altbier but based on how great it was, I think it would work great in a kolsch too. Same problem though, you need to age a long time or else use gelatin to knock it out.
Based on things I have read, K-97 might not be a kolsch yeast, but rather more similar to 1007. I hope it is, as 1007 is just excellent.