There are different hair transplant methods but mainly 3 are most common:
Follicular Unit Hair Transplantation(FUT)
Follicular Unit Extraction (FUE)
Direct Hair Implant(DHI)
In FUT (Follicular Unit Transplantation), hair has traditionally been harvested using a long, thin donor strip that is subsequently dissected into individual follicular units with the aid of special microscopes. In Follicular Unit Extraction (FUE), individual follicular unit grafts can be removed directly from the back and sides of the scalp using a small, round, 7-mm punch-like instrument. Direct Hair Implant(DHI) is the advanced for of FUE. In DHI a specific kind of implanter is used to implant the hair while in FUE holes are made and then hairs are put into that. You can say in terms of result there wont be much difference but DHI is more cleaner way of doing it.
Result wise FUT is the best no doubt in this. Here 100% result you get with good hair quality but the problem is linear scaring on back side of head. May be after 20 year when you will losse all your hair then it looks ugly. It's costs half of the FUT and DHI. if you don not want any type of scars and result that is bit lower than FUT the FUE is the best option. Single follicles are extracted from donor area so no scars. Compare to DHI it takes more days to heal in both donor and recipient area( 12 to 20 days). And in one its not a good idea for more than 2500 graft. So if more grafts is needed for you then you have to get it done in 2 to 3 sessions. DHI is the latest one. Here a special implanter is used so healing so very fast and no one even can identify after 2 week that you have gone to hair transplant surgery. In term of result FUE and DHI are same and people still think that both are same. Eevn I agree upto 50% because extraction method is same. If you want to return to work early and not noticeable then go for this. And it costs higher than FUE.
NOTE: its not the method on which you should completely relay because DOCTOR is much more important. He can make things work. So fist look for doctor and then methods.