Definitely a couple other threads on the matter. I'm going through that debate as well.
The biggest reason to go with the existing inventory would be range and battery (100 Battery versus 75 in the SR). With battery degradation being a real thing, you have to figure out how long you plan to retain the vehicle. The EPA range is an "ideal" range that most never achieve, and, you are most likely not going to charge to 100%, so, you are starting with a range reduction off EPA on a normal day, combined with real-world range restrictions.
However, the refresh models do feature the newer suspension system, the ability to charge at higher rates on a SuperCharger, and, of course, the new motor.
The Longest-Range Electric Vehicle Now Goes Even Farther
There really isn't a good answer to the question. However, if range reduction isn't going to be a concern in the long run, then, potentially the newer refresh model is a better bet. But, if you need every ounce of range, then, of course, the larger battery with the older technology would be a better bet.