As these trucks increase in collectability I think the more original the better. If you have the patience and money to keep the EAS, I say stay with it. Replacement components have improved over the years and there are companies to help you to keep the electronics functioning. Ultimately, to the collector, a truck with EAS will be worth more. Are we at that point with these trucks, I don't know. Eventually, we will be.
If, on the other hand, you're more interested in reliability and less maintenance, obviously the conversion makes the most sense.
It reminds me of the Triumph Stag. It was originally equipped with a 3.0L V8 that was a horror story of issues mostly relating to its propensity to overheat. In the '80's and '90's the move was to drop a Rover V8 into the car and be on your way. In the last 10-15 years or so there seems to be a move back to the original Triumph motor thanks to improvements in engine cooling. Collectors scour the world looking for old Triumph engines for parts or restoration. Original Stags are worth more today than converted ones.
So, this may or may not be the case with the Rover EAS but it's my feeling if you have it in your Classic and it's working, keep it. When it fails, review the market, weigh the options and make your decision. Sometimes an EAS failure can be a relatively easy fix, sometimes, you're not so lucky.