Prior to FFS I had two in-person evaluations: one with a surgeon using hairline incision, and one with a surgeon using coronal incision. Each surgeon highlighted the advantages of the method they use.
As explained to me by Dr. Spiegel a benefit of hairline incision is direct tightening of forehead skin. It's easy to demonstrate. Place your fingers where a hairline incision would occur and push up/back. If the skin on upper face was seriously sagging, a hairline incision is like an upper facelift at the time of FFS.
The downside is a scar at or near the hairline. A skilled surgeon can minimize the scar, but it's a potentially visible location and not everyone heals the same. Transplants can be added at a later time in an effort to cover the incision but that requires additional downtime and expense.
With any incision there are limits to how much tension can be applied. A good surgeon won't pull skin excessively tight. This also limits how far your existing hairline can be pulled forward. You can't simply yank it forward without considering the effect on forehead, eyebrows and other soft tissue... to avoid a permanently "surprised" or unintended facial expression.
Dr. Simon at FacialTeam explained to me: a coronal incision is further back, hidden under hair. The strip of skin that is discarded can be harvested for follicles and transplanted immediately following FFS. The transplants at FacialTeam are optional and I met some younger patients who didn't use this option - they didn't need the additional hair. In my case 1,500 follicles were transplanted from the discarded strip of coronal skin to fill my triangles (widows' peaks) -
page 5 of my FFS post. 1,500 follicles were put to good use instead of going in the trash.
I am not aware of the coronal method causing a significant increase in hairline height with or without the transplant option. To demonstrate that, place your fingers in the area where a hairband would go - that's where my incision is. If you apply tension to skin in that area your forehead and hairline will move, but not by much. I am very happy with the way my eyebrows fit my new skull shape.
My hairline is growing in nicely and it's a feminine arc. I no longer worry about a windy day and in a few more months I'll wear a ponytail when I go running. But the best answer for me is not necessarily the best answer for someone else. We each have unique backgrounds and goals.