I think the main difference between Minako and Usagi is the fact that Minako is more brash and tomboyish, whereas Usagi was ditzy in a cute, princess-y way. Which makes sense, obviously. ;P
Though, when I was reading the first chapter to Sailor V, I couldn't help what wonder what the original plan for the story was going to be, before Sailor Moon became a thing. Correct me if I'm wrong, but Naoko wrote the first two chapters of Sailor V before she started working on Sailor Moon, right? There are some things in Sailor V that make sense in the context of the rest of the series, that wouldn't really make as much sense if Sailor Moon didn't happen, such as how Minako's transformation phrase is "Moon Power", yet she's the princess of Venus. Assuming Sailor Moon wasn't already in the works, I do wonder if there were any alternate plans for the storyline that got dummied out later. I think that would've been cool!
Anyway, I thought this was a pretty good first chapter! It established Minako's personality pretty well... And also, I just love Artemis. The scene when he first spoke to Minako was just golden.