I've regularly had problems with the adhesive: I either bump it off, or scratch it off in my sleep, etc.
I also had a weepy sensor wound after the first few sensors.
Plus, because water can get to the sensor metal wire through the central hole, it would not read BG for 10-30 min after a bath. I suspect the weepy wounds were caused by the bathwater getting bugs into the wounds.
Mike from the other diabetes site recommended Optifix on his blog. I got Optifix tape which covers the sensor completely, with a couple of mm extra on each side. Perfect! No problems whatsoever since then.