I've been to Ljubljana and loved it--it's a beautiful city. I would have liked to see more of the countryside, especially that lake with the tiny island which I can't remember the name of, and Piran because it's like a miniature Venice architecturally. It's a small country (only about 2 mil people) so there isn't a ton going on all the time, but it's a wonderful place to visit and will be gorgeous in June.
I've been to Ljubljana and the Lake Bled area. The only real low point was that we didn't have more time (we were there for three days). I absolutely loved the country and it's on the short list of places to return once we move back to Europe.
Oh wait, we went to Piran too. It's really pretty but there wasn't a ton to do there and we ended up being pretty bored the evening we spent there.
Almost word for word (minus Piran) this exactly. I loved Ljubljana and would have spent more time there, although to be honest we probably did all we could do in the 3 days we were there. It was beautiful and just loved the country and the people.