how do these differ in flight as well as rolling?

I don't roll either one but the road runner is much more controllable than the monarch was for me.

I carry both(in Champ plastic) in my bag............ the Roadrunner turns over way easier for me, although the Roadrunner has been in the bag(beat)for 2 years & the Monarch is fairly new. I have a new RR on order, i'll have a better comparison once i throw both that are worn similar.

I carried the monarch for a while but it just didn't find a place in the bag. I do carry 3 Road Runnders though, from new to beat. I have found it to be one of the smoothest turnovers or straight shots there is for me. It has a ton of glide. For a roller, I only throw a 1st run mini star stamped Sidewinder. MONEY!

I find the Star Roadrunner much easier to throw an anhyzer with. It always seemed to me that the Monarch had a bit of fade. I generally use a mid 160's star Road Runner, and tried out the Champion Monarch 175g, and 154g, and the Star Monarch (175).

I absolutely love my star roadrunners. I reach for this disc for 75% of my drives. Very straight for me.

Im a lefty, seems like most lefties, love to throw roadrunners, Does any one agree with me on this?

I'm a lefty, and I love throwing Roadrunners on a hyzer flip line for a slow turn.

However, the Rogue has replaced the Roadrunner for this shot. I noticed that the lines were fairly similar, and the Rogue won, mainly due to the fact that it more versatile for me.

Not a lefty, but I also find myself reaching for a RR in more situations these days, especially in calm or tailwind conditions.
Carry a beat 175 Champ and a newer 169 Star, both of which are money for hyzer flip straight shots or long annys. I've noticed that I get nearly as much distance out of these controlled shots as I do with Bosses and Destroyers, with greater accuracy. In slight headwinds, I go for my 175 Champ Monarch, which has more resistance to turn and a tendency to hyzer out at the end of its flight. All 3 discs get used heavily, especially in wooded conditions. In anything more than a 5-10 mph headwind they're basically useless, unless being rolled, but otherwise they're my workhorses.
I've also recently added a 175 Champ Viking (after losing my 175 Star Valk a few months back), and have found it to be a near-perfect bridge between my Monarch and 175 Champ Teebirds. Great mix of HSS and controllability. Also doubles as an understable forehand roller.
Hope this helps :).