I wanted to put in my two cents - I also purchased an SRD370 from them - with extras it came out to ~ $1300 US. My NAZA2 GPS module was also defective as someone else had claimed in another review. I cannot fault Helipal for that, as they do not make the product, DJI does. I received fairly good troubleshooting information from them and quick email response times (within 1 day accounting for the HK and US EST time difference). All said, everything took about 1 week to resolve due to shipping transit times but they sent me a replacement once they narrowed down the issue - at first they thought it may have been the main control board so I had sent that back first.
In my opinion, for the breadth of products, competitive pricing, and selection that Helipal offers on their site, the transit time and shipping costs from HK to the Eastern US is a manageable trade-off for me.