Plus Escort S1/S2 injection is a Bosch unit. Diagnosis is (mostly) easy and can be done at home with only little equipment.
Bosch still provides parts and service.

Fords old non-OBD EFI units can be a pain in the arse nowadays as nearly all of the Ford dealers threw away the old test equipment. Mostly because it was no longer working. "Upgrading" the FRST to an aftermarket ECU is easier than doing this with an ERST as the FRST already is running an electronic unit and has a CPS etc. Not a big issue unless you absolutely want to keep it 100% original.

There's less FRST on the road and therefore making it a little bit more special although ERST seems to be more popular and more expensive. On the other hand: most of the people will not notice the difference between an FRST and an XR2i.