The best soil is the one that works best for you. Not much help I know but everyone has different preferences. You can construct a good soil yourself. Shy away from pre-fertilized soils. It is difficult to correct imbalances if things go pear shaped. The most important ingredients in any soil are a good pH buffer agent, and appropriate drainage. Manure humus provides one of the best buffer agents and perlite together with a little sand supports good drainage. Also important is to set and maintain a re-potting schedule as your plants break down the pH buffer over the space of 2 - 4 weeks. The schedule will depend on how long your veg and flower your plants.

Assuming 4 - 6 week veg it could look something like this: starting pots for seedlings > 7.5 cm pot @ 2 - 3 weeks > 15 cm pot @ 4 - 5 weeks > 25 cm pot @ 6 - 8 weeks. This assumes that the plant is in flower for 2 - 3 weeks before going into the final and largest pot. If you want those measurements in American that's seedlings > 3.5" pot @ 2 - 3 weeks > 1 gallon pot @ 4 - 5 weeks > 3 gallon pot @ 6 - 8 weeks. Many skip ahead from seedling directly to the 1 gallon pot. Not a problem but you will have better root development if you go the intermediate step.

It is worth noting that you will see a slow down in observable growth after re-potting. This is due in small part to the stress placed on the plant by re-potting. More importantly, the plant suddenly has more room and healthy soil for root growth. Energy is temporarily diverted from above ground growth to root growth. This is a good thing - bigger, stronger root system = bigger canopy, and increased overall yield.