After getting my beak wet with EECH, and learning the basics of rotary wing aviation I decided to pick up ToH in the Steam bundle for $5.
Bottom line, when it comes to helicopters I feel that ArmA 3 is simply a better product.
My biggest problem with ToH is it's funky collective controls. There seems to be an unusually long delay from when I change collective to the aircraft actually reacting. It makes landing or maneuvering in tight spots difficult and even impossible.
Maybe I'm doing something wrong? However, I've had no issues in EECH, and I've had none in ArmA 3, where I can put my bird down in even the hairiest spot without difficulty.