I am looking at buying movement speed ruins and not sure if its worth it.

Well, the only champion i've truly seen benefit from it was singed, and uhm... udyr. Since both of then have strong melee spell (singed pull, udyr bear stun) those would be the only heroes I can imagine that could use it. Overall I would say not worth it especially for their price.

Yes. Especially for champions that rely on positioning / kiting.

I always use movement speed runes, hate it when i get outrunned...

Movement speed is incredible for some champions definitely runes worth buying.

If you're playing anyone very positioning central, a.k.a most of the champions that are interesting and entertaining to play, yes.

The difference is pretty substantial, especially in those early levels. You lose your health quint advantage, but it's worth it, really.

They're one of the few runes that don't get over shadowed by items all game unless your stacking PDs

Movement speed runes can significantly help support champions.
I have a page with 3 MS Quints mostly for Kayle and Alistar.

MS Quints dont lose their awesomeness all game, unless you never buy boots, but thats just stupid of you.

Theres nothing more annoying than a champ with 10hp to run away from your range because theyre faster.

Ghost + Mastery > MS Quints IMO