The Precision Xtra was the meter of choice, but recently the Keto Mojo has got a lot of attention. The problem with both of these is the cost of the ketone strips. I am currently using the Care Touch Ketone Testing Kit from Amazon because the meter was $38USD and the strips are $38USD for 50 strips. They all are supposed to measure glucose within 15%, so I doubt there is much difference in accuracy. Not sure if there are standards for ketone accuracy, but I don't really care about the number itself as much as when and what causes changes. So far, I have been happy with the Care Touch, but I cannot say how it will hold up long term. If you measure often, you should consider the price of strips.