I have not measured the time exactly but W10 takes for ever to load for me compared to Zorin 15.3 Ultimate. I wouldn't say Zorin boots up particularly fast either so it must be a hardware thing, but a very much noticeable difference. I will come back to update this if I remember to take the measurement but I'm really talking about 10~20 minutes until it becomes usable and responsive, where as Zorin is maybe half that.
It's surprising because the specs are not terrible: i5 and 12GB RAM, although HDD. However on another computer (which I'm using now) it's a lot faster (I would say a good 2 full minutes) even though the hardware it's about 5 years older: i7 and 8GB.