Regarding the games they publish they are certainly second place after Nexon.
I only really like Dragonica and Allods from them, though. Iris and Flyff are way too 4S for me.
Their prices are indeed quite high. They didn't use to be like that back when they only had Rappelz and Flyff, but now you can easily dish out more than 10000€ and still not be able to buy all the stuff in the cash shop (of a single game). Permanent 2x Exp in their games costs around 80€ a month.
Their service is fairly average. Their forum software is horrible. But at least the GMs are fairly active. I often think the GMs aren't really involved enough in what is actually happening, though. Regarding most question they can just reply with "submit a ticket" to you. I assume they are just volunteer GMs and don't get paid for it or even live close to the company headquarters.