That's a huge and critical difference. Open source down to the hardware is the only way you can be sure that what you're getting is actually Tor and not Tor +

That's a huge and critical difference. Open source down to the hardware is the only way you can be sure that what you're getting is actually Tor and not Tor + secret backdoor. (Though I suppose you still have to trust the hardware manufacturer, but the buck does have to stop somewhere.)