Hi flyertalk! Long time post-reader, first time poster!

I may soon be traveling for work from JFK or EWR to VIE in J class on Austrian. I plan to credit the miles to my MileagePlus account. Would it be smarter to book as a United flight or an Austrian flight? Will be flying in the coming week or so, assume ticket prices will be high ($4k+). I took a look at the United-Austrian page, but couldn't fully figure out how to optimize earnable miles/premier qualifying miles.

Thanks for your advice!

hardworking21