Hi Jim,
I wouldn't call the Fyrestorm "difficult" to prime but it does have a propensity to emit a Really Big Orange Flame until it settles down to a cook flame, meaning don't dare use the thing under a vestibule with white gas. Big Flame events can be reduced by fiddling with the amount of priming fuel and pump pressure.
In all, the stove is simply easier to use with a canister.
Cheers,
Rick

