Best Arrival Berlin Airport

There is no rail connection at TXL.

In most cases, you will simply not have a choice (or, if you do have a choice, the difference between the two airports is likely to be less relevant than differences in flight times, prices, etc.).

Yes, choose whichever one works best with other factors (cost, arrival time, etc). Unlike in some cities, there isn't enough of a difference to make favoring one over the other worthwhile.

If you like being where history happened, choose TXL, which was opened during the Berlin Airlift to provide additional capacity for delivering supplies to West Berlin. Of course, the current commercial terminal was not a part of that operation, but I feel like I'm on hallowed ground when I'm at TXL.