I suspect that the Ace would have failed quickly in the market, at least as an end-user machine, even if it had matched the ZX Spectrum for graphics and memory. It was extremely difficult to corrupt memory in BASIC unless one got too eager with POKE; but every memory set in Forth is basically a POKE.

Might have been a popular hobbyist machine, though.

There were extensions for the Speccy to use Forth instead of BASIC, I remember such ads.

Don't remember if it was ROM replacements, or plugged into extension port on the back.