I need to update.
I've had my Istick for 2 weeks now and the 510 pin does get pushed down a bit. The only problem is with my KF 3.1 clone but it's been an issue with all my other mods, including my MVP2. The solution for me is to use a pick and lift it up a bit every once in a while when I swap between the KF 3.1 and any other tank.
Otherwise, it's been a really, really great experience. I've decided to get a DNA 40 device and settled on getting the VS rDNA 40 when it's released but I might pick up another Istick for a backup. At $30-$40, it's so worth getting. If you're worried whether it will work with your atty's, yes it will. I haven't noticed any rattlesnaking at all with any topper I have (KF's, Aerotanks, PT3 mini and a dripper).
I know PBusardo gave it a thumbs down but I heard he took it on his vacation this week so it must not suck that bad.