I didn't realize you could get Taptic Engines. I had wanted some about 10 years ago while I was working on a haptic data glove project, but Apple kept them under tight wraps because they own the patent and wanted them exclusive to their devices. I ended up using small pager motors, but I really think Taptic Engines would have made for a much better experience, both because they are smaller and because they are 3 axis linear vibrators, instead of a single axis rotary vibe.