If you use re-frame with reagent (and you should) then the ideas aren't that difficult to grasp. Om.next is more oppinionated regarding where you're allowed to

If you use re-frame with reagent (and you should) then the ideas aren't that difficult to grasp. Om.next is more oppinionated regarding where you're allowed to run queries (subscriptions in re-frame) and transactions (handlers in re-frame), and forces you to build a single large query from the root component (wheras re-frame allows you to run several queries from every component).