First, thanks for this thread. It was a wealth of information for me before I purchased my iStick50 about a month ago.
I've experienced just about every non "send it back to the retailer" issue that's in this thread, and most of them I can write off as human error / oddities / learn to press the fire button.
Yesterday, I learned a new trick while screwing around with atomizer coils. Reproduction steps are below:
1. Set iStick to some reasonable wattage (I like mine in the 5.5-6.0W range).
2. Confirm that the settings are locked via pressing the up/down button and seeing "Locked" on the screen.
3. Confirm that the unit is in variable wattage mode (big number on screen ends in "W" -- in my case, it reads 5.5W)
4. Remove any atomizer / tank from the unit (as if you are switching tanks).
5. If you don't have an eGo adapter, screw one in (I've only tested this with mine in)
6. Click the fire button once quickly to power the screen. Mine says 5.5W on the screen.
7. Take a metallic object and gently swoosh it around inside the eGO connector. I've used car keys and a loose atomizer with very good results.
8. Confirm that wattage has changed significantly. Mine maxes out at 20.0W if I swoosh around a bit.
9. Re-install tank.
10. Confirm that unit is now locked in at 20W.
Based on the above, I would imagine that folks set to VW run a slight risk of modifying their locked-in settings when swapping tanks.
Unless nobody else can reproduce this. Then I'm going to jump on the piss and moan bandwagon.