Big vote for the DEXCOM!
I tried the Dexcom in 2009 for about 5 months, but I quickly abandoned it after I had lipodystropy on both sides of my abdomen. The doctors (and Wikipedia) said it was because of the insulin, but I've been using Novolog forever and had the pump for four years at that point, so I'm not sure why it would magically start happening in the span of one week. I stopped using Dexcom, but I continued using Novolog and the pump, and I haven't had problems since then.
My guess is that doubling the amount of needles in my abdomen caused this, and the Dexcom needle was fairly long (and very difficult to insert). Only one side of my abdomen has gone back to normal.
But now, I'm trying the Revel pump and CGM. I'm not happy with the needle length, and it has caused bruising and bleeding, but I am happy that 1) it covers much less real estate than the Dexcom, 2) the monitor is built into the pump, and 3) the sensor has an inserter. However, I'm mystified that the transmitter is allowed to naturally flop around, and you have to use a massive IV3000 bandage to secure it. Incredibly clumsy design. Luckily, I've managed to use a simple piece of medical tape to secure the transmitter to my body.
Another thing: If you don't angle the insertion properly (close to 60 degrees), then the insertion point is exposed! Plus, I've had a lot of bleeding around the insertion point, and the blood dries up underneath the base. Not aesthetically pleasing.
Overall, lots of pro's and con's with both Dexcom and Minimed. Not sure why they take so long to improve their designs, especially in this day and age of advanced technology.
Well, Medtronic has a new sensor, the Enlite, which has been in use in Europe for a couple of years now, which has a tape built in to secure the transmitter. And it lasts for 6 days instead of 3.
But, of course, it is lost in FDA wasteland hell, so no one knows if or when it will ever become available in the US.
Neither one of the CGMs is as good as I would like them to be, and yes, I would really like to see both companies working on improvements. I'd like to see more accurate meters for that matter! But with the FDA the way it is, and the healthcare industry the way it is, I advise you not to hold your breath.
Actually, I have exactly the same question. So far I've been on the OmniPod for >5 years, but my A1C is getting worse and worse (recently 8.4) so my endo has suggested a CGM. But he seems to think I should abandon OmniPod and go with Medtronic pump because with the Elite you can get them to talk and it'll shut off insulin pumping if you get too low. Well, that's all very nice but it doesn't seem like a good enough reason for me to abandon my OmniPod. So I'm checking into what experience others have had combining OmniPod and CGMs.
Update: I switched from the Medtronic to the Dexcom for a couple of reasons: first, it's WAY more accurate for me -- I had a lot of missed lows in the 50's on the Medtronic. I can't speak for the Enlite, but that leads to reason number two: The Dex sensors last longer. If you reuse the Enlite, you get 12 days; if you reuse the Dex, you get 14. Plus a lot of people use the Dex for even longer than that while continuing to get good results.
The fact that they don't speak to each other is not such a big deal -- it really doesn't take much time to enter a BG reading from the Dex (or even better, a finger stick) into your pump, and then your carb count -- a very minor inconvenience in the whole scheme of things. Both my Dex and my t:slim are in my pocket, and don't bother me in the least. So I'm sold.