I was waiting for some others to weigh in who perform recitals a little more frequently than I do, but why not throw in my $0.02? In Canada we got rid of the penny and would round that down anyway, so you get a sense of just how valuable it is.
There was a time when decisions about what key a piece of music was in was an integral part of writing that piece. Different keys had different associations and in a way their own "tonalities" especially before equal temperament was the norm. If you have a chance to listen to an organ or harpsichord in a different temperament system play in a variety of keys, it really is an eye opening experience. While there are some keys that are more resonant for certain instruments, when the majority of what we do in a solo context is accompanied by a piano, you do lose some of that to an extent. Instead of a whole orchestra of strings behind you either brilliantly ringing in a particularly string friendly key or sounding a little less resonant in a key with a few more flats than we typically like to see, a piano accompaniment isn't going to sound a whole lot different if it is in A or Ab, where an orchestra would.
A lot of us talk the talk about being comfortable in all keys, but very few of us walk the walk. In classical music, the majority of what we play in orchestras is in comfortable keys, and if we find ourselves somewhere we don't like to be we're usually not there too long, or it's a slow movement anyway. In solo repertoire, it's just about unheard of for something to be written in Db, F#, or really more than 3 in either direction. In Jazz there's a bit more flexibility, but a lot of standards happen in their standard key, and vocalists that call a tune in a different key are occasionally looked down on for "not being able" to do it in the "right" key. YMMV depending on the musicians you keep company with, but I find myself less and less comfortable with the "challenging" keys as time progresses, to the point where I am actively making an effort to rectify that.
As for how it sounds on a recital program, or a program in general, it really can make a big difference. I played in a band for a while that played almost everything in D. The vocalist found those two keys comfortable, they sit well on all the instruments that were in the band, we were making arrangements from maybe some lyrics and a melody anyway, so it seemed like a good idea. Occasionally we would do something in A or G because of where the melody sat, but that gave it more of a V or V of I type feel/sound than really moving to a different key. Seeing as there are only a finite amount of ways you can string the same notes together and each instrument has things that sit better or worse on it, unintentionally we started using some of the same fills/licks/solo content in different songs, because what are you going to do? We played a show once where everything on that show was in the same key. And wow, did it really get to you after a while. A few of the musicians in the audience really got into it, saying it drove the show and connected things in a sort of subliminal way. A few others made comments to the effect of "you do know there are more than those 7 notes, right?" but ultimately it ended up having an impact that we hadn't put much thought into.
Some musicians put a whole lot of thought into it. I think it was Zappa who would occasionally plan sets where each song was one semitone higher than the previous one, regardless to what it was originally recorded in. Others intentionally move to keys that compliment each other or keys that don't when putting together a program, which is also a good idea. A lot of us put together a program of music we like, we think will go well together or contrast nicely, pieces we are interested in learning, or some of the "standard" repertoire that is expected on programs, and don't necessarily think about the keys they are in even if they often are quite similar.
When it comes to commissioning or arranging something, we really have to be proactive about this. If you do not feel comfortable in the keys that don't get a lot of mileage it might not make sense to put something there, but at the same time a lot of composers and arrangers do not go there because of how frequently we complain about keys. I can't think of the last time something in B+ landed on my music stand and my reaction was "awesome, let's do this!" instead of "well, we'll get through this because someone decided a semitone in either direction was too much work". If I was a composer and saw the types of reactions certain keys get on a regular basis, I would avoid them too.