I like many others have a fondness for the MFT1552 and 1553, they don't have the "bells and whistles" of the newer testers but make the most of what they have, just about everything you want for everyday testing. To use a "Top Gear" motoring term they are a "drivers" tester ie. every time you use it the experience is pleasurable and leaves you with a smile on your face.
I don't get this with the MFT1720 or 1730 which have far too many hidden settings buried in the maintenance function. If the tester is a company instrument used by many people, you have to waste 15 minutes or so just resetting the tester the way you like it every time you go to use it or be irritated by the current set-up, and either way it sure annoys the hell out of you.
The only practical additions on the newer testers are the earth resistance and earth leakage (requires an add on Iclamp at extra cost) functions, everything else is marketing spin in my opinion.
Forget Bluetooth data collection on either a MFT553 or 1730, although there are slight improvements on the later tester it's still a nightmare to set-up and use. The data entry is so clunky and counter-intuitive that pen and paper is still quicker and more reliable for the average tester.