Depends more on you... And your life style. If you don't mind taking a pump off to bolus for food then the 640g may be ok. If you want one that is discreet and you se a remote to do pretty much everything, then the Roche is good.
Also depends upon your size as currently Roche only have flexi cannulas for their insight. They will be bringing out a CGM to talk to the insight in the near future.
The 640g has a CGM that will talk to it if you think you may like a CGM sooner rather than later and if you can self fund or are an an exceptional individual.
If you swim then you may want to look at waterproof of pumps.
There is also Omnipod that Addenbrookes do, but I believe they too only have flex cannulas.
It largely depends on your lifestyle.