MS. quints, are they worth it?
If so, against sort of what lane matchups would they be recommended for?
If so, against sort of what lane matchups would they be recommended for?
I wouldn't use MS Quints on supports. Level 1 stats are incredibly important in duo lanes. As a support player, your most important quintessences are Ability Power and Armor.
I'm just going to quote Doublelift on this. "You chose runes to strengthen your weakness." Movement quint can help some champs that are fairly slow.

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I think MS quints are mainly used by junglers like

As mentioned before if you are a solo laner vs a skill shot champ MS quints are god-like.
I'm not ranked, but if you look at my match history you will see I beat a Platinum in a 1v1, Annie (me) vs Velkoz (Platinum player) - Velkoz is quite possibly Annie's hardest counter. I ran MS quints and dodged nearly every spell. If I was a bit slower I would have been fried multiple times.
I personally like MS quints on just about all of my tanks. With my tank mastery pages, I can get around 340+ movement speed at level 1 without boots, and that can make a huge difference.
i use MS quints for jungling... faster clear times and i can more easily get in for ganking.
Autoattack melee champions also use them very well, as do most general champions without inherent movement speed boosts. Just about anyone could use them, to be honest, but it would come down to the strengths and weaknesses of your team comp, as well as their general synergy with your build.
For instance, AP Xin uses them better than AD Xin because he must keep attacking at all costs, or he doesn't heal fast enough, and he doesn't cast fast enough. AD Xin, on the other hand, depends more on a devastating single combo, and his standard kit gives him the strength to work that sufficiently as long as it stings. Bringing AD or Armor Pen Quints would be more beneficial to AD Xin, probably.
They're mainly for junglers and some supports. On them they're sooooo worth it. For laners not so much. Maybe on ranged tops for easier kiting or something.
MS quints are powerful as hell man
Teemo and Udyr lol
To me, they're better on junglers and supports since those two roam a crapton or you can get them if you want to kite (I took them on Teemo to start at 350 movement speed and kite Lee Sin for days), however with supports AP based ones with decent or a lot of damage (Zyra, Nami, etc) probably need AP more, as I've played movement speed Zyra and starting off with only 5 AP (0/9/21) or 14 AP (9/0/21) sucks, you do no damage at all and ruin any kill potential your lane might have so please, don't use them on her, still, they are an extremely viable option because they can fit on any champion as it's movement speed and all champions will benefit from more of that however some not as much as others so you would result to different quints.