1) Sake is a "cleaner burn" than other alcohols - No tannins or histamines in Sake, so no redness, puffiness, stuffiness or headaches. Low acidity means little or no acid reflux for most people. No sulfites for those with sulfite allergies. Low or no "cogeners" (fermentation impurities) means no hangovers.
2) Built like beer but drinks like wine, Sake is it's own unique thing - Aromatic and complex like a wine but brewed similar to beer, Sake tastes like neither one. There are thousands of Sake breweries across Japan and many different styles. Chances are there is one out there for you.
3) Sake is great with many types food - As mentioned above, Sake doesn't just go with Sushi. The unique umamai characteristics of Sake means that it actually enhances your flavor perceptions of many foods more than wine would.
4) Great packaging - Sakes come in some of the prettiest bottles you will find in the alcohol world, many with unique shapes and fantastic labels. They also almost always have screw caps or pull tab tops, so no corkscrew necessary!
5) Sake keeps well after opening - Didn't finish your bottle? Just screw the cap back on and stick it back in the 'fridge. Sake doesn't oxidize like wine and doesn't go flat like beer (unless you have a sparkling Sake). You usually have about 3 weeks to finish off an open bottle before you start to notice any deterioration in flavor. But don't AGE your Sake like wine. Sakes are meant to be drunk fresh, so consume any bottles you buy within a year of purchase.