As FYI so it is not a surprise. When we switched from the Animas to the Tandem, the cartridge change (which we do every three days - both cartridge and infusion set) is not as simple and quick as it was with the Animas.
Initially it was a bit aggravating on the Tandem because we were used to the Animas approach for the cartridge change.
If you read various threads on these forums related to Tandem cartridge change, you can see there is the official Tandem way to do the cartridge change and then different people (such myself) have made slight “tweaks” to the process which they may feel is preferred either for better results or faster change. In any event, just be prepared for a learning curve here which otherwise might have been unexpected.
In my opinion and now that we have been on the Tandem (and off the Animas) for some time now, it is just one more thing that you get used to and not something that I personally would use as a deciding factor in which pump to go with.