Disc brakes also take some time to "bed in." So they tend to feel like garbage at the beginning of the very first ride. Then they get progressively better over the next ride or 3 depending on duty cycle & frequency.
After the 3rd ride (50-100th sizable brake application?) at the absolute latest, they should be as good as they are going to get.
What I mean to say: Grandma that rides once a year in Florida versus a motivated and skilled rider having legit full day at the mountain park are going to have vastly different break in periods.
I have a 11% grade 1/2 km hill by my house. Between the beginning of the first trip down & the end of the 3rd there is a noticable change in how well the brakes work.
For the record, all my bikes now have 180mm rotors & Spyke, Spyre, or BB7's. Cheapo Tektro OEM and 160mm rotors tended to fade unacceptably, turn blue & warp.
Road & mountain have different duty cycles. Road discs tend to have more thermal mass than their mountain counter parts owing to long & fast heat accumulating descents. Mountain tends to be quick short hard duty with ample cooling opportunity.
It's so easy to swap things around, I wouldn't think to even consider bike shop brakes at purchase time. Run 'em in your area/terrain/riding style & see if they meet your needs. If not? It's super easy to upgrade.