After all you have gone through, I would not choose this other donor. You want a proven donor that has a DE pregnancy. A -ve result and only 6 eggs? Maybe she didn't really take all her shots? DE is too expensive to take a chance on a donor with those stats. You deserve someone with a much more promising DE record.
Although I am going with an unproven donor, she had 22 antral follicles so I feel I have a reasonable chance at a good number of eggs. My 2nd choice donor, in case this one doesn't work out, is a proven donor who had 38 eggs in her last cycle and the recipient is now pregnant with twins. There are so many agencies out there, with thousands of donors. My ethnicity is very unusual but I still was able to find a few suitable donors to choose from. I did have to register with over a dozen agencies and it took alot of searching and patience, but I eventually found someone.
I know how horrible it is to have a donor not work out or cancel, I had one donor that went missing and didn't even show up for her clinic appointment! I know you just want to move forward quickly, but you really should take the time to choose a donor who has a much better record.