I'm not using the sensors, unfortunately. I can't afford self funding but when I heard Medtronic was giving starter packs along with the 640g, I was hoping to fund 1 sensor per month. Alas, this isn't happening in Glasgow.
There are good points about the 640g:
There are 3 different bolus increments, 0.1units, 0.05units, and 0.025units. I use the 0.025unit increment because I am insulin sensitive and use small amounts. This means that instead of the 3.1u that the Veo gave me for my usual breakfast, the 640g gives me 3.175u. I had been thinking I'd have to change my breakfast ratio but that's not the case now, due to the slight increase in bolus.
Although I've had the 640g for over a month, I'm still learning about and getting used to it. I'm sure there are lots more pros but I can't think of them at the moment.
There are some bad points I've noticed.
The clip is nowhere near as good as the one on the Veo. - My 1st 640g fell off my dressing gown when I bent to pick up the bath mat. It seemed to be working OK but was replaced a couple of weeks later when I noticed air was entering the tubing when the pump was detached for a shower.
Unfortunately air is coming in the tubing with the new pump too, so it looks like this is a fault in design.
There's a lot more button pushing compared to the Veo, but I presume this is a safety measure (I suppose this should be a "pro" rather than a "con").
Getting back to the hot weather, it was about 24 degrees. My pump wasn't in direct sunlight, it was under my T shirt. I've been in hotter temperatures with the Veo and it didn't heat up the way the 640g did yesterday.
I'm sure I've read that Medtronic doesn't recommend the use of Frio but maybe that was because the Veo wasn't waterproof.