Dhi punch vs fue punch?

All FUE procedures produce similar scars.  It is the size of the punch that will determine the scar (not the name of the punch).  Many doctors and clinics use their unique FUE punch.

The term DHI, which stands for Direct Hair Implantation, is another name for the sharp implantation technique. Its distinctive feature is that it employs hair implanter pens that create the recipient sites and simultaneously transplant the grafts, instead of creating premade incisions. The excision punches do not differ.

It's more to do with punch size than a brand name. Really it should be a non-issue when researching surgeons, as a surgeon with enough experience can do a really nice job regardless of the type of punch they're using. Plus, the difference in scarring between different punches is relatively minimal and no matter what you will have some scarring.

At times companies or practices advertise what they use as the best option around. And they might be right. In their hands that device or punch may have been better than others. However, I believe a surgeon should have a variety of punches and devices to be able to chose the best for each specific hair and patient.

In general, the smaller the punch the smaller the scar left behind.  However there is a limit to it and going too small may increase the risk of transection (losing some of the hair shafts in each graft) The most commonly used punch sizes are 0.8 and 0.9 in our office. However it all depends on the hands of the user. We switch between sharp and blunt punches and different sizes in addition to manual, motorized and robotic for the best result. The choice of the punch depends on your hair and the physician using it as it is not a “one punch fits all”.

it's just a punch. 1mm or less. FUE of any type involves the use of a punch that's 1mm or less. With ARTAS, the harvesting is either with an 18 gauge needle or a 19 gauge. There's is no real difference in scarring, but those harvested with the smaller needle might heal a day faster (2 days instead of 3)! So, no difference. 

Anybody can make claims.  The scars that occur from FUE happen because a certain amount of skin is removed. Smaller punches make for smaller scars.