Tried the SDD (970 EVO 1Tb) and it did make a HUGE difference. I synced the complete blockchain in two days. My 20bps internet was the next limiting factor, but two days is ok for me.
Such a summary was needed at the end of this topic, exactly when I wanted to ask about the time difference between synchronization on HDD and SDD.
I think 2 days is acceptable, taking into consideration slow internet, sync can be possibly improved to 24 hours or even less on really good performing machines.
Still, I am surprised that there is no other way to sync faster. I was sure this is possible with the help of bootstrap files but maybe not for Bitcoin Core client?