The Bosch system is very reliable and when problems happen, pretty easy to diagnose. I've had mine for about 7 years now and have had only one problem with it that was easily fixed. I hang out on another wedge board, and I read all the time about people having issues with their carbs, rarely with the FI.
With that said, I'd say if you can pick up spare bits and pieces at a good price, do it. I have a complete extra system (including intakes and all the sensors and an ECU). Just in case. If your ECU goes out, they are pricey from a vendor....better to have one "on the shelf."