The WTBTS track record, IMO, proves that they are not what they claim to be.
With all their erroneous predictions of the end coming, flip flopping on certain doctrines, the blood issue, Malawi / Mexico debacle, covering up of paedophilia, criticising other religions on their philanthropy such as by their contributing to establishing hospitals and other numerous charities - whereas the WTBTS hasn't, to my knowledge, donated a single penny, UN NGO registration - yet they've been slagging off the UN in their publications for decades, the inhumane practice of shunning and by extension the destroying of marriages and families etc. (Others are welcome to add to the list as I'm sure I've left out many other issues).
So who are God's true worshippers on earth today? I don't know. One thing I do know is that the WTBTS is not.