Granted, the plugs aren't sitting up there staring you in the face like they were in the VWs I used to own, and you do have to move a few things to get to them. But none of that is really too hard. With the right tools (a ratchet, a 6" extension, and a sparkplug socket) (plus a torque wrench to finish the job off correctly) it hasn't proven to be really that difficult.
The really tough ones, I hear, are on the turbo models, as each plug has its own coil pack that gets in the way.
The usual cautions: Don't change plugs on a hot engine, and be sure the threads are properly engaged by hand before applying the ratchet or the torque wrench.
2003 XS Premium MT >200k miles! ● 2005 Impreza 2.5 RS MT ● Robin-Subaru Powered Generator