I have had the ERSA RDS 80 for many years. No problems with it apart from the fact that the DIN socket is plastic and not locking. It is a bit loose after so much use.
I do not know the quality on the lower models, but I have had a good experience with the brand. Tips are about 20 euros here in Greece.
If you go for something Chinese, I would suggest that you buy it locally and from a respectable store. This way you can be sure that you have a valid CE certification. And you can double check the grounding just to be sure. And of course, make sure that you test your RCD regularly.
I bought the ZD-917 this way a few months back and couldn't be happier. I pretty much haven't used my ERSA since. The tips are dirt cheap and seem very durable with proper cleaning and maintenance (I tend to be a bit overprotective with them anyway)
The Yihua and Rhino devices that Dave reviewed are from the same family, just newer models.