The pendulum of opinions on this discussion ultimately represents your personality / preferences. I'm analytical; thus (and not really surprising) I very much appreciate the data / information my EDM730 provides. Take a look at the [attached] pictures - perhaps it will provide some good perspective for your decision... (For full context, I am operating an O-470-R in a 1963 C182F. Also, the vintage CHT gauge was rendered INOP with the 730.)
I'm analytical, which also means I'll try to quantify my perspective for you to draw your own opinion rather than just projecting my opinions unsolicited and without data for reference. I immediately eliminate the trite arguments about ROP vs.LOP operations and fuel savings. I operate my engine at lower altitudes in warm weather to temperature references for performance because the 730 allows me to do that. I can choose to prioritize fuel burn or go-fast. F*** fuel savings arguments as basis to spend thousands of $$; we fly airplanes and if you were worried about saving fuel you'd be in a Prius with all the people sitting in traffic below you.
(1) The ability to understand all 6 cylinders' performance at any stage of operation gives me
interesting context at times I haven't expected it. For example, inspect #5 cylinder on a cold morning in the first picture. My personal preferences determined I wasn't willing to go full-throttle until it's operations came up to a temperature that met my expectations.
(2) In the second picture, note the left tank fuel level from the 1963-vintage gauge to the right of my 730. I was flying with fuel selector on "both". Compare that to the amount of fuel used (just over 1/2 of capacity) and it is obvious I had an accuracy issue. My 50+ year old gauges are failing - in this case, the "left" fuel gauge started reading "empty" at 1/2 tank and the comparison to
my 730 identified it PLUS provided the data necessary to validate this condition when I refueled.
(2a) I also have 2 IFD540s, which can utilize the data validating my flight plan calculations in real time. You can see this on #2 display's data tab expanded on the right. If you spend most of your time within short distance of your home base, this may not be important. If you (like me) frequently do trips of ~750+nm in a single day, this information is excellent.
(3) Determine whether you want to pay for PRIMARY instrumentation. Your budget of $6,500 is woefully inaccurate if you are paying an installer. I'm currently looking at the 930 as my other cluster is dying (reference #2) and I don't want to pay to replace '60s era gauges with used '60s era gauges (again, personal preference). The installation cost (labor) for 900-series systems is going to be minimum 40 hours of labor on top, which means it's a ~$10k investment.
I understand budgetary concerns. My 730 came with my purchase. I have four kids going through college, so when I purchase upgrades I go for refurb'd options and pursue every avenue to get better information without the "brand new" premium that drains my budget.
One final and, admittedly, self-serving note: if you are interested in an option that will be more in line with the resultant increase in value at selling time, I happen to be upgrading to a 930 and will be selling my 730. You'll get a far better ROI for your budget, and get the data/context you may desire as well. Feel free to contact me directly to discuss.
