A&K probably makes the best China guns out there, and their Masada is no exception. The only complaint that I have, (and it's a huge one), is the hop up; it sucks! You have to mod it or replace it with the CNC hop up, and those are out of stock everywhere.
It is a bit overpriced, IMHO. For 300, you could get the performance of a KWA, Classic Army, or a Tokyo Marui.
Honestly, about 50 bucks that you are paying goes toward the "Masada" name and concept. It's a CoD fanboy's dream gun, so they upped the price to make a little more cash, knowing that people would buy it instead of the Magpul PTS Masada, which is around 480 bucks.
If you upgrade it, it's definitely on par with a lot of Classic Army's.