Not sure if I really made this point in my first post but I'm not gonna read it again to figure it out, so I'd just like to emphasize planning prior to deciding on a setup, and of course, always provide yourself a margin of error or cushion in your measurements and calculations. Assume that plants you intend to grow to 30" tall fully matured, really end up being 36" tall, and so on with variables similar to that.

Also do your homework on the various growing styles and the way they affect yields over periods of time, and have a plan for that in mind. Remember that there are wide variations in growing mediums/container combos, starting with the difference between soil and hydroponics, and so on from there. Keep your expectations realistic, and just know that a premade grow system, for example a fully equipped grow tent, is what it is and doesn't allow for much in modifications in the future as you may learn that you'd prefer one thing over another, or decide to expand.

All that being said I think that the grow systems I have seen, at least the quality ones that actually make sense, are great systems and literally include pretty much everything you need to get started. I think they probably make it easier to get into indoor growing, and learn how to garden properly indoors since they think of everything for you, and you won't be forgetting a critical piece of equipment. I'd like to note that I have never used one of these systems myself, nor have I seen very many of them in person. In fact the only time I've ever seen indoor grow tent systems was at a new hydro store I visited this last sunday, but they looked pretty neat.