When I first began oil painting I bought some of Bill Alexander supplies at Michaels Art Store. That was back when places such as Michaels still had people working for them who actually knew something about art.
I remember that when I asked one of the sales women for advice regarding the supplies, she told me that this Bill Alexander method was a good way to start, but that usually most artists will discover that they want to expand their capabilities after they complete about 6 to 8 paintings using this style.
She was absolutely correct. After creating about that number of paintings, I found myself wanting to create something that showed a better result. I can still remember the day and the subject at which time I switched over from that style, and moved on.
However, contrary to some of the opinions indicated on this thread, I believe that some of the techniques in terms of brush handling, especially regarding his criss-cross strokes in creating skies, are really quite sound in their operations.
The Bill Alexander method, or Bob Ross method, truly do represent a formulaic method of painting, and for that reason it tends to hold the artist captive to the brushes, knives, paint-loading, skip-trowleling, and other specific "moves" that are so characteristic to that method.
For example, once one learns that method of skip-trowling with which Bob creates a mountain, or the specific method of loading a brush with paint, and the proper way of tapping the brush on the canvas to create bushes and foliage, one quickly discovers that once learned, it can't possibly get any better. You can become an true expert at that method, and not be capable of creating anything much better than you second, or third painting was.
The paint-handling methods of Bill Alexander, or Bob Ross, do not carry over very well to those who may wish to paint animals, or human portraits, still lifes, etc. While that method is suited for painting landscapes, it is not very useful for other subject matter.
However, looking back, the Bill Alexander method actually did give me a degree of confidence in handling paint, especially in the painting, and blending of skies. There is a slight degree of "flamboyance" that is actually required in the painting of a sky, using a large brush, that I truly appreciate, and I got that from performing a few paintings in that style, before I strove for better work.
The Bob Ross method actually does teach a few things, but just don't get stuck in that method forever.