A Mag Spark came with a gun I purchased a while back. Although it worked, I have enough trouble dropping things like percussion caps, let alone small pieces like a primer firing pin assembly component, that I wouldn’t consider using one in hunting situations without spares for the droppable items. I carry extra caps (or flints) when hunting. Drop the Mag Spark firing pin assembly into the leaves, mud or snow, and you are potentially done without a spare.
Recently did some limited testing at the range with one and noticed a change in the point of impact when compared to regular percussion caps, not a negative, just something you may have to account for.
Another thing to consider, while percussion caps are difficult to find today, 209 primers disappeared for a stint not that long ago. If you are committing to using primers, suggest a thousand minimum, unless you don’t shoot much. Also would suggest Federal brand based on experience for consistency.