Not to mention the benefit of a 2 F / 4 H / 1 C riverside manufactory for a settler-and-worker spamming REX capital ...
If you really want that, Collective Rule is superior on any speed except quick. A free Settler, plus an equivalent
boost during the REX phase, plus a saved SP is going to trump the Manufactory. On quick, you take Landed Elite over a Manufactory hands down unless you're going with an OCC.
(The reason vexing is taking Meritocracy in G-Minor II is because he can't take Landed Elite, since he wants to exploit the Legalism trick. I think that giving away LE is going to hurt more than the Legalism trick helps, but we shall see.)
The value of a Manufactory diminishes pretty rapidly as the game wears on, because it confers less advantage as other tiles start to generate large amounts of
. Placed on Grassland, it's merely a +2
boost for the capital once you hit Chemistry in most starts. That's not worth a SP choice, so you'd better get maximum mileage out of it early to justify the pick.
On lower levels where it assists with building
infrastructure
and all the early Wonders, the Manufactory is better than a GE.