His unreleased songs sound better to me, because more time is spent on the production and putting together of the songs.
Not true, quite a few of the unreleased songs are unfinished from a production standpoint and don't even have proper mixdowns. Pac was known to drop a rhyme on any beat in any state and then have the production finished up and adjusted at a later date, one which never occurred often at Death Row
due to the amount of material recorded
and then the songs never being released. Pre-Death Row is another story, but the same will still apply at times.
"Holla At Me" is the perfect example, the original version sounded tacky and rather plain - the finished product was amazing.