Best way to pace yourself?

Hey there, I'm still having trouble completing full groups of burpees. I was wondering in general, do you think its better to do exercises as quick (with good form) as you can til fatigue then rest, or take things slowly with no big groups of rest?

At the moment I typically do 10-15 burpees in 35 seconds, then rest 30 seconds then another etc... until the set is finished. I'm wondering if its better (will I get stronger faster?) to just take that full 65 seconds to do the 10-15 burpees and hope to finish the set in one full swoop?