I was surprised at how heated this topic got and originally didn't want to add to it. But I couldn't understand why Hanna would update the 736 to the 774 and lose so much accuracy. I looked at SuncrestReef's details in his initial post and came to a different conclusion.
Range: 736 is .00 to .6132 ppm phosphate; 744 is .00 to .9 ppm phosphate
Accuracy: 736 is .01533 ppm phosphate; 744 is .02 ppm phosphate
Reading resolution: 736 is .003066 ppm phosphate; 744 is .01 ppm phosphate
Conclusion: the 736 is more accurate, by just over 30%; the 744 has a wider range, extending the range from .6132 to .9, both of which are greater than needed.; the resolution, or size of each digit that displays on the meter doesn't matter as it is smaller than the accuracy of the digit displayed; the 736 requires conversion of the number displayed to get ppm phosphate.
I chose the 744 because it is easier to use and sufficiently accurate for me. I can see why others would prefer the 736.