is it worth visiting the Lingnan Impression Park or is there any other better worth visiting park in GZ?

If you want to see ancient buildings and antiques, you can go to Chenjiaci (Chen Family's Memorial Temple) which is also the museum of Guangdong Folk Craft Museum. The old style buildings in the impression park is newly built in fact. You can also go to Shamian Island of Guangzhou, an exotic place with old western buildings. If you will not stay longer in Guangzhou, I would not suggest Lingnan Impression Park, for there are others more worth of visiting.