Honda ECUs have proportionally the same fatality rate as the EMS. There is just fewer EMSs in use, so you hear of them a bit more. Either way, killing a Honda ECU or the EMS is usually a result of some electrical mishap in installation or other activity.

The EMS was designed to interface with all Honda sensors, injectors, etc. It also gives more complete error diagnostics than a Honda ECU ever dreamed of.

The EMS can also take in sensor readings from multiple sources and have that info be used for correction maps. Most chipped ECUs have 3-D maps, but with the EMS, you can have up to 6 dimensions of correction for altitude, temperature, humidity, throttle position, boost pressure, EGT readings, wide band O2. Get your maps right, and it's set to make max power every day that the engine setup is the same.

The EMS is more expensive, sure. But in the long run, if you have someone knowledgable setting up your correction maps, going faster is just a matter of turning up the boost, instead of turning up the boost, going to the dyno, spending another 2 hours making pulls, burning another chip and then being on your way until the next time you want to do something different.

It's the same with any high-power build, you can save money, make lots of power, and be reliable, but you can only choose 2 of those 3 options.