All I'll add is that I've used the expensive-ish AMP/TE crimp tools (for insulated Faston, insulated ring) and they basically work flawlessly every time. If you just need to do like 10 crimps, then hell no, don't buy it...But if you need to do more, or if it's for an actual production job, I'd still at least think about the official tool.
The official tool is partly expensive because it's actually robust, but mostly expensive because TE/AMP wants to lock you in to using TE/AMP connectors/terminals for the rest of your life. So, it's a bit annoying, purely out of ~principle~ but hey the tools are pretty good.