The only problem with that statement is the quality bit. The M12II, for example, comes with Nippon Ichi and Rubycon caps (Rubycons for the secondary caps exclusively), and is generally very good; the soldering is top notch and there are no reasons for complaints.
The only real improvements in build quality of the X-650 are a slightly more modern internal layout (and thus the higher efficiency), the better fan, and all Nippon Ichi caps, and that's pretty minor, all things considered.
So the build quality improvement is pretty marginal, but I 100% agree with getting it for an improvement in functionality (semi-fanless mode).