I don't think SF is "much" better than Combat Casting, but admittedly the +1 difference is a small advantage compared to being able to benefit from the bonus in other situations.
Generally, I think either feats are worth for a spellcaster who really plans to cast a lot of spells in the middle of melee, which is much more typical for divine casters than arcane casters.
If you just want Concentration for those times when someone interrupts your casting, or grapples you, or the environment is hazardous etc, I would be content enough of maxing the skill (which feels on the average somehow less expensive than a feat), and that is something I would however suggest to every spellcaster unless it has very few skill points; also once your rank is high enough those feats become less useful than at lower levels.
However those feats could be useful exactly if you can't afford a high rank, for example because you are multiclassed with a non-spellcaster type.
There could still be some time when Combat Casting is preferable. Perhaps if you have already a high rank, and you just want to be sure to cast your healing spells in melee...