I haven't found a Machete to be silent/stealthy playing infamous. If I use one I need to break contact to lose pursuers. I'll experiment a bit.
I'm mostly proactive stealth, I don't always engage, but I do recon everything. When I do engage enemies, it's usually with the silent MP-5, but I do throw sniping into the mix if all I really need to do is kill a single target and then duck away unseen.