Some collectors perceive Beckett as being stricter in certain aspects of grading, such as centering and surface condition
Avalanche Caller can animate your snow lands into 4/4 elementals, while Boreal Outrider makes your creatures enter with a +1/+1 counter if snow mana was used to cast them
For me, Im only casting it with X equal to five or greater unless Im in a pretty dire circumstance, since returning the creature is the more compelling part of the equation
Grumgully, the Generous is probably the most obvious example: we make Spirits, they auto-get a +1/+1 counter, and therefore they'll get more because they're modified
Unless you have multiple overlapping buffs, players usually just keep track of buffs in their head
We can expect the value of showcase cards to be at least 30% more expensive than the normal version, and thats being conservative