The 50 1.8 II is the superior and more reliable lens.
I would hazard a guess that you are in a minority with that position. The 50 F/1.8 is sharp and a stellar value, but it lacks virtually everything else.
As much maligned as the 50 F/1.4 is, the 50 F/1.8 has greater issues. Pentagonal bokeh, cheap build and a comically slow (and noisy!) focusing plague this lens.
It's a great starter lens in getting use to primes, using larger apertures, etc. but unless you are shooting non-moving objects at stopped down apertures, I'd choose the F/1.4 ten times out of ten over the F/1.8.
But the 1.4 breaks more often the the 1.8 and yet you say the build quality is better? bang the 1.4 on the nose and it breaks. fragile as glass....how is this better build quality? I've had 3 1.4's they all broke. i have an old metal mount 1.8 for 25 years...never broke. yet you say the 1.4 has better build? what does that mean?