It's a weird one and a testament to how much variance we see in our hobby. I've done probably a dozen batches with Köln and with the exception of 2 occasions I've got ~83% attenuation instead of the ~77%ish I usually achieve despite having lower fermentability worts, it's been solid as a rock from initial pitch to kegging.
Never had fermentation take more than ~24 hours to start, even when I've accidently cooled down to 15°C pre pitch and not run with any heating.
Never had it throw any esters other than a vague hint of stone fruit or apple/pear, even at 25°C.
As I mentioned it's been my house NEIPA yeast for about 15 months, precisely because it's been exceptionally reliable and predictable for me. Every beer I've made with it has been "great" or better except for one which was oxidised by a CO2 fitting failure, which you can hardly pin on Köln. IMO it's much better than either Verdant or New England in Lallemand 's range for hazies. And I literally dump it straight into the fermenter in dry form during transfer, no rehydration, no starters, no additional oxygen.