I swear, it's comments like those about intonation and blending that make me feel like my ears are wired differently, not to mention everything else going around me making me feel like I'm in a different world sometimes.
Sure, there's a little bit of tuning instability moving from one location to another, but that's only for a short time, easily rectified by showing up early and letting the instrument acclimate for thirty minutes or so, and only really affects the overwound E string. My plain strings never have a problem and are a lot more stable day to day on my old flatback than any steel strings I ever played on were on any bass. Never had an issue hearing the pitch clearly so long as I've got enough volume that I can hear myself at all—I've had an easier time since making the swap, even.
Bowing is harder but it's made me get better than I ever used to be so I can't really complain.
Trimming the fibers and sanding the string can be a pain sometimes, but I only ever feel like I need to do that every couple of months at most.
And regarding the sound in an ensemble—that might be as much a matter of the bass being played as the strings on it. Martin Heinze in the Berlin Phil plays gut strings, at least on the D and G, it's clear as day in his headshot on their site and any videos they've got with him in the shot. And where I've been worried about the sound sticking out too much before playing in musical or orchestra gigs, I've instead been told that my sound blends and supports the ensembles really well—extra surprising, when I'm the only bassist and everybody else is on steel strings!
(Or maybe it's because I'm the only bassist, who knows.)
Even my old teacher, who started when gut strings were the only things available and hated them, said that he actually liked them and how they sounded on my bass. Now I just really want to get ahold of Mark Foley one of these days and have him play my bass for a while and see what he thinks.
Regarding the philosophical side of playing on gut strings and the use of animal bits in general—I'm not at all a vegan, but I've got a load of problems with the wider aspects of the farming industry both on the animal husbandry side and just on the actual crop farming side. I think it's a massive shame how much the typical western (and especially American) diet has moved to only consuming muscular tissue from any animal slaughtered, both for general reasons of the healthiness of what we eat and the sheer aspect of respecting that something with a brain and senses and some level of processing experience that is not all that dissimilar from our own had to die for us to be able to eat it. Treating any part of it as a "byproduct" to be tossed out or (at best) repurposed in some other way as fertilizer/pet food/etc. is insulting to both the animal and to the way humans lived and relied on them for millennia. The conscious decision to use parts of the animal for functional and/or artistic reasons is much more respectful than what we usually let happen to them without considering it whatsoever.
In relation to the above, while I think people should eat more organ meats (they're good for you! If you want something good for your heart, eat heart! Good for your liver, eat liver! They're much more nutritionally dense than regular muscular tissue! And they taste good! Even kidney if you actually know how to prepare it!), I also think the vast majority of people need to be made to come to terms with the fact that the meat they eat didn't just spontaneously appear in the restaurant fridge or in the little styrofoam tray with plastic wrapping at the supermarket. Meet the animal you're going to eat. Or at least witness the process it actually takes to take something living and turn it into food from start to finish. Pick out your own chicken where it's walking around and do the entire process of turning it into a nice roast bird yourself.
But my brother's family does butchery and meat packing, not to mention hunting, as do many of my friends, and one of my uncles raises cattle and gives us in the family a half a cow every year at Christmas to go in the deep freezer, so I'm actually somewhat used to these things.
