Actually I live there and I'm surprised with tripadvisors invitation to review it. Actually it's not bad idea to get first hand info about.
Ljubljana Old Town is not so known on world turist higliht map as Venice or Wiena but it's surpriseing positive when you want to discover something new. It's placed around river bank and there you can find a lot of different places to visit concentrated in walking distance or just walk around and enjoy excellent food and drink in many cute restaurants and pubs for mostly reasonable prices. There are a lot of bridges over the river, old food market, you can take a boat trip or walk/elevate to the castle on the hill and do or see many other things as museums, galleries, shoping, drink a coffe on the top of the oldest skycrapers in the Central Europe.
Ljubljana has excellent position for day trips. In one hour driveing you can be in Alps or on the Adriatic coast. Bled is 50 km away, famus Postojna cave is 40.
Anyway my opinion is you won't do mistake if you visit Ljubljana for at least few days ...
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.