I love sumac too. The leaves turn a gorgeous red in the fall. Just be prepared to do a fair amount of sucker management, unless you want a sumac grove! Your sumac will send sprouts up out of the grass around it.
Poison sumac has white berries, like poison ivy, so no worries.
Sumac lemonade is very simple to make (no boiling!) But the flavor very much depends on picking the berries at perfect ripeness.
Here's a nice detailed description of how to make a perfect pitcher of sumac lemonade, with great tips on harvesting the berries.