I'm new to this but this is my recent experience with Jiffy Pots. I germinated 4 seeds, 2 NL's and 2 Blue Mystics, by paper towel method. 3 germinated after 2 days one did not, a Blue Mystic. As I had to leave for a couple of days I planted the 3 germinated seeds into my soil mix and put the one ungerminated seed into an expanded Jiffy Pot and then planted the Jiffy Pot directly into the soil mix. I put them under my CFL's. And when I returned they had all sprouted. This photo is of the Blue Mystics at close to 4 weeks. The one on the right was started in the Jiffy Pot.
As far as those nets on the Jiffy Pots go, the roots grew right through them.
I did try to germinate a previous batch of seeds following the instructions on the Jiffy Pot container. Not a good move. I only resorted to the above as I didn't think the seed was going to germinate, I had to leave it for a couple of days and I thought, WTf, either it works or it doesn't.
I don't like the jiffy pellets, I like the burpee ones better myself. I've never had any issues with the burpee ones, expand, drop seeds in place on heating mat, sprout, grow.