We've been to Barcelona several times, so we decided to visit what we've never visited before, so we went to the Palau real (park with a small castle not open to the public, but free), and then we headed to the finca which is just next to it.
The guy at the entrance told us that half of the buildings were close (only the stables were open). He gave us an explanation, showed pictures, he did a great job. But the inside is just not worth it. Don't waste your money (I don't say time as you finish the visit in less than 5 minutes) and go to the monastery which is in the same street a few minutes away from it, it cost the same and it's worth it.

The current Royal Palace in Barcelona at one time was the country estate for Eustebi Guell. While Gaudi did not design the structure, Guell did hire him to design the entrance gate and horse stables.

This shows Gaudi at his beginning in a mudejar style design very similar to Casa Vicens. The site has a number of tile designs in exposed brick. Also you see several parabolic arches that Gaudi loved so much. However the highlight is the dragon gate which also shows a Gaudi feature with wrought iron designs. This one is perhaps his best and it was one of his first. I love it because he put such detail into a minor structure for the overall property. Once you see it, you understand why Guell latched on the architect from some of his greatest work.

Also notice the design in Guell's initials and the flower pot on top with a iron plant and flowers. Simply amazing. Great to see the beginning.

Finally while I would have paid the fee to see the interior, I visited just after sunrise before opening and really got to see without paying. You can really visit at anytime to see it.

It's an ok place but not really worth the 4€. You can see a few tools and that's about it. The dragon outside is cool but you don't need to go in.It costs money to enter the garden and there is not too much to see inside. The draconic gate is spectacular though. Not necessarily a must hit place within Barcelona, but if you find you have time to spare or are on the hop on hop off bus it could be a nice stop.