I prefer the Skywatch cave. You can access it faster and don't have to die/reload checkpoint. The only thing is after 20-30 minutes, tons of hive and fallen spawn in and duke it out. Kinda fun, actually.
Not really. It takes about the same amount of time to get to Skywatch from the Old Russia spawn point as it does Crota from the Moon spawn point. The difference is that you only have to travel to Crota once. Then every single time after that you spawn right in front of the door.