That mat will work fine, I have 2 and use them every year. The description says 10-20 degrees higher than ambient temps so listen to Ed about over heating. I wouldn't put the seeds directly on the mat, they'll probably get burned up and won't germinate.
Here's another method I used last year when I was selling plants and would germinate many varieties at once. I used those cheap aluminum pans with holes punched in the bottom for pots, I could grow 25+ seedlings in there till transplant time. I bought a plastic tote with a lid for a germination chamber, set it on a seed mat and it worked great. I could fill it up and it would hold moisture good.