I have hard+slightly acidic water...it eats brass and copper which is why I had to rip mine out (besides it being the thinnest "letter" copper). For me, the plastic fittings are actually preferred.
I just replaced an outdoor faucet this spring, and had an issue getting the replacement to seat...the exposed inside threads of the brass adapter where the old faucet stopped were plated with rust after only three years and kept the new replacement from seating. Brushing it out with an old copper sweat fitting brush allowed me to get the replacement to seat fully. So for me, less brass is better...
I just replaced an outdoor faucet this spring, and had an issue getting the replacement to seat...the exposed inside threads of the brass adapter where the old faucet stopped were plated with rust after only three years and kept the new replacement from seating. Brushing it out with an old copper sweat fitting brush allowed me to get the replacement to seat fully. So for me, less brass is better...