TBH, it's really hard to tell how accurate any of them are. There are differences between them dependant on their underlying formulae. I think the key to them all is how you use them. Something I have yet to perfect.
Any advice on that front would be much appreciated
Thanks for the link that you have shared here.The currency meter presents the data graphically which is more easily understandable than numeric values but it also represents in in numerics as well.