I have the Big Three — Blichmann Beer Gun, Tapcooler, and the Boel iTap. For a quick fill, nothing beats the Tapcooler. Setup and cleanup on the other two is significantly more effort. That said, 80% of the time, I use my iTap now. It has the highest learning curve and highest amount of initial setup effort, but it works really well.
I’ve mounted mine to a flat steel bar which extends about 4” to either side. There are holes drilled through each side of the bar to allow it to be bolted to whatever I want. I put threaded inserts into the collar of my keezer and also into a short section of 2x2 pine, which I can lay between two foldable plastic sawhorses which have a factory-provided cutouts where I can insert the 2x2. That way, it’s portable. I just bolt the steel bar to the collar or 2x2 with a pair of threaded knobs. Today, I bottled in my garage where I have a few kegs just chilling. The key to minimizing foam for me with both the iTap and Tapcooler was to be sure to FULLY pressurize the bottle before opening the tap.
I haven’t used the beer gun in a few years now. It’s more for high volume, IMO, and it foams no matter what I do.