Both

Depends

Both, but that depends how written both are. Just because one is sympathetic doesn't really make a good written character all the time, and not all PEs are well written too (look at MCU Malekith).

Personally, I prefer a combination of the two. Someone who is absolutely revolting, but is still unmistakably human. The MCU's Mysterio is one of my favorites. He's an egotistical, self-serving, douchebag, but he only goes after Peter when provoked.

Oh that's a good one I gotta admit. I like those examples.

I like both but it depends on the character and sometimes sympathetic villains like Zuko are more interesting than the pure evil villains

I feel like complex characters are nearly always better than those who are all good or all bad though sometimes i do enjoy a really hateable Pure Evil like Ramsay Bolton.

It depends on how well they are written, how the plot and heroes turn out to be, what symbolism do we have, and overall a lot of things. It's also possible to have one sympathetic villain and one PE at the same franchise/setting. For example: In "Jurassic World: Dominion", we have a sympathetic one (the post-redemption Wu) and a PE one (the cinematic Dodgson).

@HowardHamlin Pure evil characters can be complicated too. Many villains who fall under fake tragic are complicated.

I prefer both, so long as they are well written and engaging.