what do you get for subscribing,  either as a hero or dungeon master?

Details of what the subscriptions unlock can be found here, but the summary would be

Hero Tier

• Remove all adverts
• Unlimited character slots
• Save public homebrew to your homebrew collection
• Access tools and features while they're in alpha, ahead of non-subscribers

Master Tier

• All features from Hero Tier
• Activate content sharing in up to 5 campaigns (until end of year, at which point it will return to 3), sharing all content owned by all members with all other members.