It has been about 6 weeks now since we made the switch to the MiniMed Guardian. It was a hard decision - we loved the Navigator - but could not wait for replacement products. Here's the verdict - Guardian over the Navigator. Why? A box of sensors is about the size of a package of poptarts. Much easier to store - and alot less waste. If on accident you did not insert the sensor all the way in with the Navigator - it was trash you, had to start over with a new one. With the Guardian you can just pop it back on the inserter (or push it the remaining way in) and continue. Sensor life - I can't believe how long our sensors last. I have had the kids take the transmitter off to recharge (15 minutes) to keep it going. We have actually said wow, I can't remember how long you have had that thing in - why don't we pull it? We need to stick with the company that can get us our best bang for our buck Transmitter - Navigator really was huge - the guys hated it. With a bigger profile it was also easier to get knocked off. My youngest said the guardian is like a couple of quarters - he forgets he' s wearing it. Because the transmitter is smaller the guys are willing to use it on their stomachs - they are not so embarrassed. Tape - small transmitter, alot less tape. One piece of Tegaderm HP. Receiver - durable, durable, durable. This is the same thing Minimed uses for its pump. It is rock solid. 2 hour start up - what a huge difference. Repeat alarms can be set for what you want. We have our high alarm set for 2 hours. Once you acknowledge it, it wont alert for the 2 - or whatever you choose. Receiver Battery - aaa battery - and you can change it without having to restart your sensor What do we wish were better? Longer range - but seriously, we are used to it now. LOUDER ALARMS - for nighttime. Long needle looks scary. I can't believe I am saying this but if we had our choice between Nav and Guardian it would be the Guardian!