I believe Concerts generally give a 'bigger' perhaps more mellow sound vs the 'brighter' sound of the traditional Soprano-size ukes.
Of course not every Concert will sound the same, nor will every Soprano. Hence the fun, the challenge, the heartache, and the heartbreak of UAS. Not to mention 'bank account-break'! lol : )
I generally play the Soprano nowadays, but I did play the Baritone and Tenor for quite a while in the past. I perform with a violin-shape Tangi Concert at my regular Restaurant gig. I carry around either my Applause Adamas Red acoustic soprano or my Kala Soprano Travel uke.
I suggest you play around with the various sizes and see which feels and sounds most comfortable to you. I know some uke players only have a handful (maybe up to 5) and some have only a couple, and others have room(s) full of ukes.
The key is to have fun, and keep uke'in',