Marty, the grass seed mats are just fine to use. they do help to keep the seed moist as it germinates also if you have a slopped area the mats can be pinned down until the seed germinates. the main drawback is price. Tends to be expensive considering the amount of seed. Also you are stuck with whatever seed mix they use and it may not be the best for your site. Probably best used as a patch for existing lawns.