Visiting Vis remains one of my fondest memories of Croatia. The island looks like some earthly paradise, far removed from the everyday world. The furthest of Croatia's islands from the mainland, it offers a simply wonderful environment in which to spend time resting, relaxing and taking things easy. The fact that it is so amazingly underrated, underdeveloped and little visited by tourists is precisely and undoubtedly what makes it such a wonderfully charming place today.
The island of Vis has two main towns: the town of Vis itself, which is quite a trendy, upmarket port town containing a few Roman ruins (it is also the place to which ferries from the mainland sail); and, on the opposite side of the island and reachable via a breathtaking bus ride, the quaintly adorable yet very lively and animated little town of Komiža, which I strongly recommend you spend some time visiting. It has dozens of excellent fresh fish restaurants located down by its harbour, and the generally relaxed atmosphere and ambiance these offer stands in contrast to the below par service you sometimes encounter along the rest of the Croatian coast.
In my personal opinion, Vis is without a shadow of a doubt one of the essential places to visit in Croatia, and it is definitely somewhere that needs to be seen before the crowds of tourists inevitably arrive.