Counter pressure filling is better for a few reasons:
1. It reduces the exposure of the beer to ambient air / oxygen meaning the quality of the beer will be maintained far better than if poured directly off tap.
2. The carbonation of the beer will be maintained to a higher level as the beer is transferred not poured into the growler/squealer.
3. Beers that are poured via a counter pressure filler can be kept for a longer period of time (unopened) as they quality of the beer has been maintained.
4. The counter pressure filler reduces the amount of beer being wasted.
The only downside to using a counter pressure filler is that we are not able to fill stainless steel growlers as we need to be able to see the fill line of the beer.