I’d want to see copies of the lab reports before deciding. VS1 is totally safe, but I’d want to compare inclusions. Also, I’d be very surprised if all the proportions for both stones are exactly the same. It’s not impossible, but highly unlikely.
If both diamonds were perfectly cut, then I'd for sure go with the D VS1 that costs less. I'd be thrilled with the fluorescence and lower price!
I hope you have seen photos and/or videos of the two stones. We would never recommend buying a diamond without those at the very minimum. That's why people are asking you for the grading reports to be sure these stones are in the ideal cut range. That's the starting point.