I use bimmerlink (and bimmercode) for convenience. I also use ISTA for more in-depth stuff using a laptop. Bimmercode/link are separate packages and purchases, however its a lifetime licence rather than a subscription and the cost is cheaper than a year with Carly. You can do advanced coding with bimmercode, that you cant do with Carly.

I also confirmed that Carly's battery registering doesn't work at all (at least on the E9x), despite telling you that the battery has been registered correctly. I double-checked in ISTA and confirmed my new battery wasn't registered. Since then I wont use Carly at all as that specific problem has been an issue for years and they have done nothing to resolve it.