Liechtenstein is tiny. The entire country is about 62 square miles (smaller than Washington, DC). It's one of the wealthiest countries in the world (per capita) and a tax haven.
Vaduz is the capital and the only real town. It's clean, quiet, and not particularly interesting. The Vaduz Castle sits on a hill overlooking the city. You can't go inside (it's the prince's residence), but you can walk up to it for views. The Liechtenstein National Museum has exhibits on the country's history and culture. The Kunstmuseum (art museum) has modern and contemporary art.

The mountains are why you'd visit Liechtenstein. Hiking in summer, skiing in winter. Malbun is the main ski resort. It's small, quiet, and less crowded than Swiss or Austrian resorts. In summer, the hiking trails are beautiful with views of the Alps.

Liechtenstein uses the Swiss franc, and prices are similar to Switzerland (i.e., expensive). A meal at a restaurant is 20-30 CHF ($22-33). A coffee is 4-5 CHF ($4.50-5.50).
Liechtensteinians are German-speaking and culturally similar to Swiss and Austrians. English is widely spoken.

Getting to Liechtenstein requires going through Switzerland or Austria (there's no airport). Buses connect Vaduz to Swiss and Austrian cities. Most people visit for a few hours and move on.

When to go: Summer (June-September) for hiking. Winter (December-March) for skiing. Spring and fall are quiet, and many mountain facilities are closed.

Liechtenstein is tiny, wealthy, and not particularly interesting. If you're nearby and want to check it off your list, stop for a few hours. Otherwise, skip it.