I don’t really use OD pedals much as I tend to prefer the gain from the amp itself. However, i did do a quick A/B comparison between my Boss DS1 and the DS1 simulation in the KPA. I placed the real DS1 in the distortion loop in stomp slot D and toggled back and forward between them. I couldn’t make them sound exactly the same but they were definitely close enough that I could hapily have used the KPA version insted of faffing around with the real one.
I’m also not a hige user of delay or mudulation effects but when I do use them they come from Strymon Timeline and Mobius pedals. However, I haven’t turned on either of those snce I got the KPA. Maybe there are some slight sonic improvements from the Strymons but for my needs they aren’t significant enough to merit the hassle of carrying extra pedals and power. The convenience of having everything inside one unit trumps any slight tonal differences for me.
I will not surprised if I end up selling mine; I've heard very good opinions about the built-in fx and I know they have been greatly improved. The consensus (from YT reviewers) seems to indicate that the KPA reverbs are not as good as the delays, and others, but I am not a reverb guy to begin with - I prefer a subtle mix of delay in place of a reverb. I bought my Strymons for some ambient stuff experimentation, and that they do extremely well. Having said that, they have been off most of the time now, so I totally understand your position.