Yeah, I think you ultimately have to take such things in stride and realize that most often there won't be a clear-cut best team.
There will always be more of a rock paper scissors relationship in cricket. For example, Sri Lanka will beat India, India will beat Australia and then Sri Lanka will lose to Australia - who's the best team out of that scenario? Hard to say, and probably not worth arguing over.
Unless, of course, there are some teams that truly just rise above the rest for an elongated period of time, like Australia has in the last decade. In spite of the occasional lost series, they've quite clearly been above the rest (2-1 Ashes lost replied to with a 5-0 victory next time). Figuring out that Australia has been the best team of the past decade and then some is pretty easy, but once the dust settles and lets say Australia leave this golden era at some point, I think cricket ultimately is one of those games that may not have a clear-cut "best team" - especially due to home and way conditions factoring in - and that's part of what makes it fun.
I think that's partly the reason ODIs and 20-20s are so popular (besides being short, of course). It's because a lot of the time it's not easy to pin-point the better team, and the theoretical best team isn't the one that always wins. There's the higher possibility of an upset, and the shorter the period of time where players have to be at their best, the more likely you are to witness an exciting upset (i.e. you only have to be at your best for 20 overs in 20-20, whereas in a test you have to keep it up for 5 days).
As an interesting side note - is there any other sport where home/away conditions makes as big of an impact in the result? I'm not talking about crowd support and feeling comfortable, although that is undoubtedly a big deal but more of pitch/field conditions in the way that playing cricket in SA is vastly different from playing it in India? Is playing a football/soccer game in England, say, much different than playing it in Brazil? Besides the obvious temperature difference, of course.