After several years of exploration, discussions and delving into the pool of poly, having many people explain their particular brand of poly, it seems that there are essentially two different types of polyamory that lie under the many variations: Idealistic and practical. I tend to fall more into the practical camp, so I'm sure this may be a bit biased in approach. You have been warned! ;)
With a more idealistic approach, the concepts, ideas, and best-case scenarios are cherished. One may even prefer to be solo than to be in relationships where the ideals aren't being met. This model seems to be related to the early poly movement, the communes of the 60's, where "free love" was the ideal. Anyone pointing out the lack of success with a particular ideal must just not be doing it right, rather than the ideal itself being unachievable, or unsatisfactorily difficult. On the other hand, there is something to be said for sticking to your ideals, and having connections with people that are rooted in common beliefs.
The main difficulty with this model is that the participants are seldom ideal themselves, bringing programming and baggage to the party. Therefore, the best case scenarios are seldom actualized, and some or all of the participants end up failing repeatedly. If one can view those failures as opportunities to grow, great! If the failures bog the participants down, it might be time to shift your standards to what actually works, versus what you WANT to work.
Practical polyamory is a bit more in the direction of Heinlein's famous TANSTAAFL- There Ain't No Such Thing As A Free Lunch. It recognizes that the relationships one has touch others, exponentially so as the network of connections moves out, so there are very few things that one does within a vacuum. For all the additional freedoms, loves, and support that comes with poly, there are corresponding responsibilities and balances that must be struck.
For some, the balancing act can feel cumbersome or controlling, but with some patience, mutual compassion, and compromise, it is possible find enough of what is desired to make that transition period palatable, and then continue forward towards an ideal from that point. It is slower, more deliberate, and less self-centered. The trap can be in sublimating your own needs to the point where others take top billing consistently over self.
What works? What doesn't? How can something be refined to improve performance and satisfaction? If only we looked at our relationships like we shopped for cars! The nice thing about people is that, unlike cars, there are upgrades available after you take them out of the showroom and drive them around for several years. No one is static, and the practical approach would be to update and upgrade relationships consistently to keep them fresh and vital, tossing in ideas that sound good to see if they also work. Discard what doesn't function, and keep moving forward.
While there are many approaches to poly, it seems that most fall under one of the two above umbrellas. Finding the sweet spot, where the best of each is available, offers the best options for success and satisfaction. Go in search of the sweet spot!