The growing conditions for mushrooms are much the same as the growing conditions for mold and fungus. So if you start with just some "spores" of a certain species in a kit (kit = spores and instructions as a minimum product contents), you must provide pretty sterile conditions for your substrate and appliances used. Otherwise you will have good chances to grow just mold and fungus of unknown species instead of the intended species of mushrooms.
If anybody actually is giving it a try, perhaps he can post what the instructions tell about
- the substrate (wood species?) needed
- the time needed to see actual mushrooms growing from the spores
I think that the success rate would be much higher if they'd offer "mycelia kits" instead of "spore kits", as this reduces the chances of fungus contamination for unexperienced growers and reduces the time drastically to actually see mushrooms growing. But on the other hand the company would have to provide always fresh mycelia kits, as they cannot be stored for long.
Success rate might be the same or less as with such VFT growing kits:
(Read the review and you know what happens most likely to the unexperienced grower.)