I have a Guardian 3 sensor from Medtronic, which I've been using for about a year. The initial insertion isn't "painful", but can definitely be uncomfortable,

I have a Guardian 3 sensor from Medtronic, which I've been using for about a year. The initial insertion isn't "painful", but can definitely be uncomfortable, and there might be a bit of blood that leaks into the sensor cavity. Once it is in, there is no discomfort. The adhesive tape which is needed to attach it to your skin is actually more uncomfortable than the sensor. Combined with a 670G pump it has been a huge benefit for me. My A1C of 9.0 is now down in the 6's. My pump broke while I was on vacation for a week, and my control was clearly worse with pens and finger sticks than the pump and sensor.