Go see JR (Johnross) at Mean Street Tattoos! He just installed my NExT last month, and I plan on seeing him again in a couple weeks to install a xSLX (and maybe an xM1, not sure if I’ll make that purchase yet). Very Cool Guy, Highly Recommend. I drove 3 hours to see him. He currently works weekends so keep that in mind when you decide to get your implant.
I suggest, make a list of use cases (what you want to do with the implant), research different equipment/tools, and prioritize what you want. You can always get more.
For me NExT was an easy choice… two-in-one, I currently use the one side for my work badge, and the other side with the KBR1 to log into my work computer.