This strange fascination with our NHS ranking in the charts is reminiscent of the old Alan Freeman 'Pick of the pops" programme which used to chart the risers and fallers in the charts each week. Except that was very simple and based on recorded sales, whereas "best" health systems takes into account a whole range of factors including access, efficiency, costs, outcomes etc. and allows supporters/critics to cherry-pick which bits of it are best.
There have been times when the NHS was ranked very highly by international bodies and other times when it has not fared so well.
It has never been perfect, and everyone's views will be weighted according to problems they or their loved ones have had in dealing with it rather than a purely objective analysis.
What seems to be clear is that, whether based on personal anecdata or more substantial analysis, it has been getting worse in recent years at a time of austerity, and possibly by coincidence, depending on how important one thinks the governing party is in it all, at a time when that government has been the Tories.
I don't really care whether we are No.1 or not in the charts, I just want a system that is good enough to meet the health needs of a (still wealthy) country with an increasingly ageing population, and I don't believe anyone can say it is in recent years.