They are actually slightly better, in that STOs get a range bonus.
My understanding from the changes post is that the BFC gets the range bonus, the weapon range is unaffected.
Are STO emplacements as effective as space-based weapons for things such as missile defense? For example, mounting a quad Gauss turret on an orbital defense base versus just building static STO emplacements with a quad Gauss turret set as point defense. Still working on understanding all the new ground units, but STO units would save me all the maintenance I'm spending on orbital defense bases for colony missile defense right now.
IIRC you can't use turrets in an STO any more, but you can mount single weapons.
The turret has extra weight per weapon for the gearing so I think turrets were always less efficient anyway.
Ground based defence has a logistical advantage over orbital weapon platforms because you can drop them somewhere and never worry about maintenance facilities and supplying MSP.
The disadvantage IMO is setting the STO targeting (which I find finicky) and the length of time it takes to build each battalion.
Just remember that they need some help getting to max fortification from some construction units.