I'd steer clear of springs. Your mileage may vary, though. Some folks like 'em. I usually don't, on anything I want to ride hard.
The OP is riding an upright city bike, "riding hard" doesn't seem likely. Keep in mind unweighting the saddle from an upright position of a city bike kinda defeats the purpose of riding a city bike. With a sprung saddle, you can stay seated and relaxed over most minor road imperfections. The joy of my city bike is that I can stay seated and relaxed.