I used to hate RPGs, but Earthbound is good enough to be fun to someone who even can't stand RPGs at all.
The story is simple, but very gripping at the same time. I really like how it's in a modern setting, and more realistic than most RPGs (but still in a fantasy world, not total realism). You start out as a little kid who can get killed by a rat or a small snake, but, in classic RPG fashion, you'll level up until you're powerful enough to save the world. You'll meet some friends along the way, who will join you in your quest.
Like most turn-based games, the combat can get tedious fairly quickly. But it's still very intuitive and challenging. And there's enough different things to do in a fight to keep it from getting too boring. The game is also extremely challenging at first. You'll die, and die, and die again before you can level up high enough to advance the story. The difficulty eventually levels off, though.
Earthbound isn't the best looking game you can find on the SNES, but the graphics are perfectly serviceable and never get in the way of the gameplay. That's all that you can really ask for in a simple 16-bit game like this. I noticed some frame rate drop in a few spots, but they're only barely worth mentioning.
Earthbound sounds great. The music is addictive and hummable, and the sounds you hear when the enemy hits you with a deathblow, and when it says you've lost the fight are done perfectly, they're instantly recognizable and they make you say "dammit, I lost". The rest of the sounds in the game fit perfectly as well.
The game lasts long, like most RPGs. You'll spend a long time in the game leading up to the final confrontation. Earthbound is also very fun to play through a second time. Overall, Earthbound has great value.
In conclusion, Earthbound is good enough to be fun to someone who even can't stand RPGs at all. But if you like RPGs, all the better. No matter who you are, no matter what kinds of games you like, if you haven't experianced Earthbound yet, do so. It's extremely rewarding.