Sona's movement speed

So been talking to a lot of people and we mostly all agree that Sona seems to be very sluggish in her movement. Even with a lot of movement speed bonuses (boots of mobility, lichbane, basically any item that gives bonus movement speed) she still feels like she's crawling through mud as compared to other champions.

It seems with other champions something as small as 5-10 more movement speed is enough to catch up to someone trying to run away from you, with Sona it feels like you need 70-100 to do the exact same thing. I'm not sure if this is an issue with her model in general, if it's certain items just not working right on (not giving the stated amount of bonus movement speed) but over all she just feels super sluggish in game.