A short list as follows:
1) A classic cycling period allows not only the population of nitrifying bacteria, but of all other life forms. Starting with Turbostart may be fine, but one should still wait a period of several weeks before introducing decorative organisms like fish and coral that predate on other organisms. In other words, give all life a chance to establish a stable population before you introduce predatory animals. Increased biodiversity never hurts.
2) Remember that nitrogen is only one of many cycles that occurs in any ecosystem. There is the carbon cycle, sulfur cycle, hydrogen cycle, etc. Just because the nitrogen cycle is established does not mean the other cycles are. Although the N cycle is arguably the most critical cycle to watch in captive husbandry, it is by far not the only cycle of concern, and fixation on it and only it is dangerous. Again, time affords all cycles an opportunity to esbalish.
3) Extending the previous idea: All lifeforms, particularly chemotrophs like bacteria, will alter the chemsitry of its surroundings. From repeated experiences, "aged" (ie mature) water is far more adept at sustaining life then new water, even once cycled. Merge the two ideas together and one may theorize that life slowly molds its environment to make it more suitable for inhabitation. This process takes time (much longer then 2 days, I can assure you).
These aren't arguments against Turbostart, but rather an endorsement to everyone to wait several weeks before adding livestock regardless of how quickly the N cycle is established.
