I have used spring starters on several engines and they do the job well and are a distinct improvement over trying to start a fixed timing engine by hand.They are somewhat heavy ,require regular maintainance which means taking the engine out of the plane,and the springs will break if wound too tight by an unsympathetic heavy hand.
Im gradually switching my magneto engines over to variable timing electronic ignitions however and based on the ease with which these start,I beleive Id go with a CH or RC ignition conversion.If your budget cant stand the full blown system,switch and battery pack involved.look at the system that lowers the timing for starting only and then unplugs.Side benefits include no chance of backfire,and no need for fast flipping.
I coached a new to gas fellow club member through the starting procedure on my electronic Quadra 400 last nite,and using the choke til it coughs method he had it started in six flips from cold.