While the rest were BASIC, the Ace went Forth
The Jupiter Ace stood alone. Surrounded by a host of BASIC home computers led by the Sinclair stable, Jupiter Cantab decided that its micro, the Jupiter Ace, would use the Forth language.
The Z80, 3K micro has an uncanny likeness to Sinclair's ZX81, which was not surprising, as designers Richard Altwasser and Steven Vickers were both ex-Sinclair employees. This compatibility stretched to the point where the Ace could be operated by a Sinclair power supply, and with a special cable, could use Sinclair add-ons such as the 16K RAM pack.
The Ace was fast, thanks to the Forth language and the Z80 running at a reasonable 3.25 MHz. It was also ideal as a control computer and had ports to allow this.
Jupiter Cantab hoped to entice a range of users away from Sinclair to its micro. These included people looking to learn a new language, scientists and those looking to move beyond that first BASIC step.
While it was competitively priced at £89.85, the leap to Forth was too big a gamble. The Jupiter Ace had a short life because of this. Its 16K sister (the Jupiter Ace 16+) was announced in June but never appeared: the company and the Jupiter Ace vanished in November of 1983. ~ Tony Hetherington, All Game Guide