In short, it's power and toughness are equal to the most expensive artifact you've got in play, and you get some mana on each of your upkeeps that never goes away
If you cast only one half of a split card, you only consider that half's mana value while it's on the stack
The prolific price rise, and particularly the recent spike, may well have something to do with the upcoming The Hobbit set, releasing in August (check the MTG release schedule here)
Confusing, right
Midrange strategies can play Lumra as a potent six mana threat that incidentally provides them with plenty more lands to help fuel their one-for-one trades and slowly accrued advantages, creating a situation where creature lands might be the only real win condition they need if Lumra gets answered
Storage Capacity Room for Your Entire Deck When it comes to Magic: The Gathering and other trading card games, having the right storage capacity in your deck box can make all the difference