Discerning whether abilities or extra power and toughness are worth more is non-trivial, quite context-dependent, and likely will be the key to properly building decks based around this new take on the mechanic, as there are ways to use it to add more power to the battlefield
Any combat with their stuff is going to drop that life total into a dangerous place
A collectors dream and a competitive curveball all in one
(2018-10-05) A spell cast using jump-start will always be exiled afterward, whether it resolves, it's countered, or it leaves the stack in some other way
If cards qualify on at least one of those categories, they are probably at least decent against Abzan
Outlaws of Thunder Junction is a perfect example of how Magic: The Gatherings blossoming popularity opens the floodgates for more quirky sets to exist