I've used the Tapcooler a few times and wanted to give an update. There are a few quirks but for the ease compared to something like The Last Straw (Which I also have). The Tapcooler is perfect for filling a few bottles for competitions, going to friends etc.
Today, I bottled two swing top bottles and two 12oz bottles. The first bottle was pretty messy as I forgot to pull a pint to cool the lines.
Quirk 1. The pressure release spring is a little too tight. I'm guessing over time it will loosen and the pressure release valve will work better. You can also tilt the bottle slightly to release some pressure.
Quirk 2. Mine may have a slow leak in the CO2 valve. I did not want to experiment too much and probably should have filled a bottle with water to verify (Next Time). It was easy enough for me to after purging the bottle with CO2 to just turn the CO2 valve off at my tank.
To Sanitize, I fill a beer bottle with starsan and then insert the Tapcooler into the bottle. I then spray the pressure relief valve. After, filling I take apart the pressure release valve and rinse everything and then let it soak in PBW for about 10 minutes. Rinse and let dry.
While filling, foam will come out of the pressure release valve but this is not a problem as then I'm capping on the foam.
So far I like the ease of use even with the noted problems. Compared to using The Last Straw the amount of waste, mess, and clean up time is significantly less.