Looks
Strength
Personality wise...
Decide one for each
I cant decide,both are solo kings and rek so...
LOOKS
Itachi hands down. Badass looks, style, swag! Minato is good looking too, but just not comparable to Itachi.
STRENGTH
This is difficult. Although Itachi has higher raw power, stronger offense and defense compared to Minato, Minato's SM + FTG will be equally as good a battle weapon as Susanoo (from a different perspective of course).
In cross combat, Itachi will be more than a match for Minato, but will be outlasted due to less stamina and effected by blindness (if we're not talking about Edo). Minato won't have Itachi's powerful strikes and devastating blows, but his weaker strikes will be effective enough to rival them due to speed and efficient delivery. Theoretically, it's a draw in terms of power but Minato takes this only because of outlasting Itachi. Practically, the result can go either way. If Minato somehow catches Itachi off guard and manages to land a quick attack, he wins. If Itachi somehow puts Minato under Tsukuyomi, then GG. If it's a constant stalemate between the two, then Minato wins because of outlasting Itachi.
In battle against other opponents, Itachi's powerful Susanoo strikes will be destructive. Full Susanoo with Yata tanking attacks. Susanoo sword (Totsuka), Amaterasu and Tsukuyomi will be extreme tools of killing. Minato may not possess the same firepower as Itachi, but will be equally effective in a different way. SM will provide him the power, FTG will allow him to blitz anyone and evade attacks. Plus, more powerful Rasengan and other ninjutsu, and stronger taijutsu. And seals. Both will be extremely powerful for their opponents. Itachi with more power and destruction killing many at once, Minato with extreme speed and accurate hits killing one by one quickly and effectively.
Overall, I'll give Minato the edge due to Itachi's weaknesses.
PERSONALITY
Can't choose a victor in this at all. Both are tender and caring, intellectual and wise, good guiders and capable leaders, knowledgeable, calm with good style. It's a draw.