3 miles on the elliptical

Today I went down to run on the treadmill and BOTH treadmills at our workout center are broken!!!! I put in a call to our property management because that's unacceptable. Anyways, I had to get my workout on the elliptical and I did 3 miles in 27 minutes. . .not sure if that is good or how it compares to running. I can't tell if its easier or harder than running. My thighs and butt work a little harder for sure, but I think I can keep a lot faster pace on the elliptical than on the treadmill. I was booking it at around 7-8 mph. . .I am sure I can't run that fast ;) But I got a good workout either way. My 5K is just one day away!!!! I am getting nervous & excited. I am just hoping I don't have to walk most of it. hahaha!