My warranty just expired on my MM522. I have to say, I have been very pleased with their pump. Compared to other systems, the menus and functions are very quick and easy to get through. I think the TSlim also looks easy like the MM is. I remember the Animas felt like a LOT of button pushing for simple 'every day' functions (like bolusing). However, Animas has a remote meter you can bolus off of (so does, MM, but their remote meter works like the quick bolus function).
The pump itself feels very hardy/sturdy. I have only had to call Medtronic support one time for an issue. We concluded the pump had 'fixed' itself and was fine. However, I told the rep I was still nervous with the pump, and she sent me replacement...no hesitation. I have had nothing but good experience with their customer service.
I do NOT use their current CGMS(I used the 7+, and now the new Dex G4). Their new one should be coming out anyday. However, I would not pick the MM just for their integrated CGMS as it is right now. I would look at the pump first, and the CGMS second if that is important.
I have a skin on my pump currently. I think this one is almost two years old...it still looks great. They are not reusable to m knowledge.
Good luck with your pump search! I'd recommend having the Reps from each pump come to your house so you can get hands on with them!