PHB 6: Beast Mastery Compared to Tasha's Iteration

 So, Beast Mastery was infamous as feeling kind of broken in the 2014 PHB - you ran the risk of losing your beloved pet too easily, and they didn't really scale up with you very well. How much of that was actual power versus perception is something I'm not going to get into here (and I honestly don't know) but most generally agreed that the Primal Companion alternative feature that came in Tasha's either fixed the subclass or at least came very close.

So, I want to compare the One D&D version of the subclass to the more recent, Tasha's era version.

Naturally, the Ranger itself has gotten some changes, but none, I think, so dramatic that it would make this comparison moot.

3rd level:

The Primal Companion feature is, I think, possibly word-for-word identical to the Tasha's version.

The Beast of the Land gets to choose Bludgeoning, Piercing, or Slashing damage for their maul attack (the Tasha's version is only Slashing). The Beast of the Sea gets its darkvision extended to 90 feet (up from 60). And the Beast of the Sky is unchanged.

So, nothing really to compare here - it's almost identical as a feature.

    I will say as a DM I'd be very lenient on letting Beast Masters resurrect their companions even if an hour had passed.

7th level:

Exceptional Training has gotten a subtle buff - rather than letting you command them to Dash, Disengage, Dodge, or Help as a bonus action that replaces their ability to make an attack, now you get to command them to do this in addition to their attack (as their own bonus action).

Now, given that they seem to be replacing "magical BPS damage" with simply letting attacks deal Force damage, the new version also allows you to replace the Beast's attack damage type with force.

11th level:

This has been cleaned up to not mention any Multiattack option, given that these are all using the standardized stat blocks. However, there's a new addition that allows the Primal Companion to get the Hunter's Mark bonus damage as force damage on the first attack that hits.

    Now, a couple things: first off, Hunter's Mark now only allows you to deal its damage once per turn, so this would let Beast Masters get a second bit of damage off of it. But furthermore, Hunter's Mark's spell scaling works differently now - even though you only deal its damage once per turn (or twice with this feature, if I'm reading it correctly,) when cast at 3rd level you add a d6 to it, and at 5th you add another.

    As such, again, if I'm reading this correctly, casting a 5th-level Hunter's Mark gives you 3d6 extra damage, so with this feature you're now getting (assuming you and your pet hit at least once) 6d6 extra damage each turn, which... is actually not bad for a 5th level spell.

15th level:

Share Spells is unchanged.

    So, looking at this, the subclass has been buffed a bit - I can't really see anything I'd call a nerf (and even if it's not as powerful as the previous Ranger playtest version, I think we're still better than the existing Ranger).

The changes here are somewhat narrow, but I think that this is probably the best version of the Beast Master we've seen in 5th Edition (I'll let someone who has more energy to do the math decide if it's a powerful subclass or not compared to the whole game).