Got my red XR yesterday; like others have said, the camera is phenomenal (I came from a 6S, so... I may not be the best resource lol) and the battery life is KILLER (mine was 60-ish% out of box at 10:30AM - by 10:00PM I was 25% with only one minor top off for about 20 minutes on a regular iPhone "slow" charger). The display is world's better than my 6S, of course, but is slightly lower quality that my wife's Galaxy S9, but that is only on VERY close inspection, not normal usage.
As to size and color, the red is definitely darker than expected - and I actually like it better that way. Very pleased with the color, as I was on the fence about it. Size, though, is still up in the air for me - it feels HUGE to me. Honestly, I would've preferred the XS, but my little hometown carrier still does 2-year contracts and it was a $250 premium on the contract to get the XS over the XR, so no thank you. I'll get used to it, and the smaller one-handed keyboard helps tremendously.
As for cases and hiding that pretty color, I have mine in a Poetic Guardian case - fairly protective "bumper" with a clear acrylic back and a front screen protector (a la Otterbox Defender, but less bulky). I think it's a good compromise for a slippery phone while still getting to show off the color. I have a student who, like most teens insist to these days, carriers her brand new gold XS Max naked... and has already broken the back glass. Mine will always be in a case, thank you very much. 🙂