I've had a few Sweet Tarts and Ceciloves over the last couple of years.
They are quite different to me.
Sweet Tart has always had a tart component. This year was the best I've had, from a small graft on one of my trees.
Maybe I've never let one (ST) ripen enough, because I can't stand waiting, but think I've hit the sweet spot with it this year, and it was definitely still a bit tart, and amazing.
Cecilove hasn't hit me with the tartness yet. Maybe I need to eat it earlier?
For me, Cecilove has been super sweet with a piney spice to it. Kind of like a classic mango, and then something extra. No fiber, juicy, and wonderful.
I am topworking some trees with CL, and will grow out some a seed for the fun of it, as I am ST. Maybe I will add some Cecilove scions to the Sweet Tart tree. My point: they are different and both great mangoes.