I have never used these products so i cannot say which is better. I never use a heat-pad and dont have any problems with night temps. Superthrive never used it . I only use Mycorrhizae on the seedlings and it's included in my potting seedling mix.After that Plants are strong and have no problems in the next size container with only promix and dont need Mycorrhizae to establish the roots in that container. The only thing I make sure when buying soil is to have a high % of sphagnum peat moss in it. And the seendling mix as a little organic matter in it but mostly peat moss.