I'm really enjoying it. I feel way more inclined to post here, I very rarely did over at Reddit. People seem a lot more receptive and willing to participate.
Only downside is that it doesn't have the history Reddit has, so I still find myself using Reddit's history for research. I haven't installed the new app though, and I haven't looked at /r/all since the API changes went into affect.
I'm no expert but I believe comments are pulled down by an instance when a user requests the information and is then cached in the DB. So not everything is, but content that's viewed by a user on the instance will be.
I don't think it really matters, but I picked vlemmy.net because it wasn't too big. I figured that the bigger ones were staring down the barrel of a huge influx in traffic, so I wanted to avoid them.
I didn't see any evidence of the admin being shady, but also wasn't too hasty with the defederate button.