I'd assume a Velcro loop would be easier in as much as releasing most zip ties involves releasing the plastic tab with a pointed tool, whereas Velcro can just be pulled apart.
My little 301 often needs the trigger held when starting warm even with the carb tuned a bit. OTOH its such a light saw it easy to do that. I set up a velcro loop on the 590, its quite a bit heaver saw etc- a great idea!