I have the GEM 603 by insight , but its not working very good, I think the
temps are way off on it, I had sent it in a year ago because the T I T was
inop and it came back with the temps not working correctly.
I saw that the new EDM800 showed % power and that it got its information from
OAT, RPM,fuel flow and so on to display the current % of power, since I fly at
65% power it would save me from figuring out the standard temp at my altitude
then adding/subtracting MP to get 65%.
so since my GEM seems to not be working correctly I was hoping to replace it
with the new EDM800, but it if cant show the % power like the advertisement
says, then a cheaper replacement may have to do.

Viperdoc wrote:

I have an EDM 760 in my twin, and it has been very useful. First, it
immediately can identify a fouled plug, or plugged injector. This saves a
lot of time searching for and cleaning plugs when the engine runs rough on
one mag at runup.

It also helps in mixture management when leaning, and helps to protect the
engine regarding the CHT's.

Fuel flow is also a bonus, particularly in combination with a GPS that will
calculate range, endurance, etc.

Overall, they add a lot of efficiency and safety.