A mixture of both would be great, plenty of memorable items in set places but make the generic loot random.
On one hand I personally feel absolutely NO need for "a mixture of the two". I just flat out prefer fixed loot over the randomized one, period.
I prefer even more when the loot isn't level gated (or worse, level scaled) and when the gap between early game and end game is RELATIVELY limited.
That said, it's not like having ANYTHING randomized would be a deal breaker. it would be more or less fine having a baseline of few random COMMON items (i.e. iron sword, basic leather armor, etc) and then to add on top of that system all the unique and hand placed magical items.
Still, the ideal scenario would be to have every single loot table in the game fixed and every item being where it is for some reason.
So we could finally avoid bullshit like slaining beasts and finding coins, minerals or weapons in their bellies.
Or searching into some commoner house and finding gems, powerful magic weapons, rare alchemical reagents.
Or exploring ruins lost for centuries and finding inside them books about the recent political issues of the region, etc, etc, etc.
There's literally NO drawback in having customized, hand-crafted loot tables in terms of gameplay. Except that someone has to do the work to fill them.
