The gap here is torque, build and money all at the same time. The Forte gives you 18 Nm of Asetek industrial servo and build quality on a different level to the mainstream, at $949; the Alpha EVO Sport 9 is a 9 Nm entry base at $399 whose main pitch is being the cheapest way onto Simagic's 21-bit encoder. One is an enthusiast base, the other an entry base, and the price reflects it.
If you want the engineering and the headroom, and the budget stretches, the Forte is the base most Asetek buyers end up on for good reason - it feels over-built in the best way. If £399 is the number, the Sport 9 is a properly good first direct drive and the start of the Simagic ladder, so you are not stranded when you want to upgrade later.
As with the other Asetek-versus-entry pairings, the useful question is not which is better - the Forte is the more capable base - but which tier you are buying in. Pick the budget, and the base follows. The Sport 9 wins on price and as a Simagic on-ramp; the Forte wins on torque, build and outright feel.