I don't trust block level, and here is why.

Suppose I have a large transaction and it updates blocks 1-100. In the middle, I have a failure and blocks 1-99 were transferred, but 100 wasn't. How does the recover solution know this? The transaction would possibly be inprocess still and cause issues when you restarted SQL Server. It might have issues with rollback/rollforward.

Blocks work great for smaller files but because SQL depends on a consistent unit of work, which may span lots of blocks, this makes me extremely nervous.

I wouldn't run production databases in simple mode if I needed to recover to a point in time. If you can lose 15 minutes of data, then run in simple, but I'd err on the side of caution and leave them in full mode, running T-log backups with my fulls.