Think of how you now take your insulin. You put a syringe in a bottle and measure an exact amount. This amount can vary by tiny increments, depending on your carb load or current blood sugar readings. We have fast acting and slow acting insulin each with varying delivery times and various "life" curves.
Now lets look at inhaled insulin. It comes in two doses. Lets call them medium and large. How fast does it get into your system? How much of the dose you received actually gets to your system? What happens if you have a cold or bronchitis?? Well these are good questions, and questions that haven't really been answered by the folks that make inhaled insulin. When you get such precise control with a syringe, why would you want to use a huge bulky inhaler that delivers a dose that you have no idea how much of it you are going to really absorb!!
Suck it up, use a needle and just say no to this stuff!!
Warren