I think you'll find most of the posts saying the Chinese VFDs are rubbish are either old, or someone quoting from an old post. There's been at least one design change in the VFDs recently, which implies they are better. Either way I've connected them up for a few people and they've worked fine, plus I'm currently using two - one the router and one on my lathe and haven't had any problems due to quality of the VFD. In addition I bought one a few weeks ago for another CNC router, and that's fine... so I wouldn't worry about it.