They are Robust, exceptionally well made and durable, in 8 months time will the janty stick still be working??? My suspicion is no, the two you buy instead of the SD will be trash and you will be on two more.
SD users will just be changing the odd atomiser and battery but their SD will be as good as new.
+1 on that score.
good on ya Jason for stocking the SD , another great name to sit behind a great device.