If you mean insertion wise they're about the same for me, I never feel either one go in. As for wearing, of course the pod is bigger so it's more noticeable than the tiny sensor for the Dexcom.
You can definitely wear the sensor for more than 7 days! I wear mine for at least 14 (or until it falls off or quits reading correctly) The funny thing is it gets more accurate as time goes on so you're right, it takes a couple days to get going and it's always much more accurate the second week.