Implanter Pen vs custom blade incisions for graft placement?

I strongly suggest, given your quite limited remaining donor supply, that you choose your surgeon not just by how he/she implants grafts, but the entire process.  I do agree, the WAW system is preferred system, and I use custom-sized blades typically 0.5 to 0.7mm, where I make every recipient site, then the grafts get implanted by my assistants using implanter pens.

There are many techniques of FUE extraction and I have used most of them including the Robotic Systems. We have started using the Trivellini System which is a multiphasic extraction that minimizes the trauma to the grafts. Our grafts are healthier and the procedure is more efficient. We have used this system for over a year now. The preferred method of implantation in Parsa Mohebi Hair Restoration Center is Pre made sites and the Mohebi Inserter.  Mohebi Inserter is a new implanter that is used to load and implant grafts by the same person. The grafts are placed into premade sites. This helps to minimize the trauma to the grafts due to forceps or other methods of placement. 

I don’t think it matters as long as the surgeon is comfortable with what they are using.  I think if you are pleased with your previous results you should talk that surgeon if you already have a good relationship with them.  
We still mainly use forceps but are moving toward blunt implanters in premade sites.