One question what is the main difference with the 640? Is that it increases your insulin intake if your blood sugar rises above 120 (6)? While with the 640 it can only reduce your basal if predict a hypo, which i already use.
I guess with the 670g you still will have to carbs count in any case.
In the US marketing, they have highlighted two things. The predictive low glucose suspend, that the 640G already uses and the "Auto Mode".
Auto Mode introduces full basal control, in as much as it's similar to what I use with my DIY rigs.
When using the "Auto" mode, it observes glucose levels every five mins and tries to maintain them at 6.5 mmol/l. This means that it reduces the insulin amounts as it thinks you are going under the target and increases them as you go above it.
You still have to enter carbs and do boluses, but it apparently will suggest a bolus if it sees blood glucose changes that aren't in line with the data that you have entered.
So yes, you still have to carb count. The reality is that insulin isn't fast enough not to. We're trying to get over that in the #wearenotwaiting world though.