I'm with you Holice, and Tartan,
- in fact I have never found a variegated thread I liked. Dark on light, light on dark, invariably! If the values in the blocks are not very different, and the values in the variety are not very different, I think it might work better.
The LQS recommends it to me, saying it will blend in beautifully, I get suckered into buying a spool, and when I try it on a sample block before I start FMQ I give up and throw it in the bottom drawer.
When I want something to shout out CLEVER!!! YOO HOO!!!! LOOK AT MY FMQ!!! then maybe I'll be ready for variegated. Not there yet!