I have used them for one of my old sites. I did not notice any significant ranking boost from, if I remember correctly, 5 edu.links.
Either way it was the last time I used them. Did not really feel good about getting tons of applications and then not paying out anything. If you are actually willing to pay out the scholarship then it is different story.
Also I remember getting my scholarship into some type of an app or scholarship aggregator where I started receiving decent amount of traffic like 300 visitors per day. Had to create filter to analytics so it would not interfere with time on site and bounce rate etc.
Actually was thinking about setting up some ads to that scholarship page too, but never did.
I've done this for a few sites, the last campaign proved that things have changed a lot since this tactic has come back into the spotlight.
Whats changed...?
Well many now say:
The will post your opportunity to a physical bulletin board on campus
They will share it with their Facebook page
They do not accept websites who are Amazon Associates
They can no longer update their outside scholarship page
So, expect poor response rates and to create a page and campaign that is better than everyone else. I took the extra step of creating a video AND an infographic/poster about the scholarship and offered it to them.
Apart from that, the links are good, you improve your overall site authority, however, if you are not going to pay out I would suggest sticking to another method. This is just my opinion but I don't like deceiving people, especially young kids!
My last scholarship offered $1,000, I got over 50 applicants and around 30 EDU links with the average DA around 65. The campaign has only just ended so I have yet to see the fruits of my labour, however, from experience, it does give you a boost across the board.
The amount of the scholarship has a "huuugee" impact on response rates. The sweet spot seems to be around $5K. EDU's start taking you serious when you give out that kind of money.