You're in the US, right? I assume you are trading through VPN? Sounds like there were no issues with getting your IP address flagged by BaseFEX, or server lag?
Let us know if you run into any concerns/problems. I'm all about having more options as far as trading platforms. Their fees aren't quite as competitive as Bitmex, but if the UI and order matching engine is decent then I'm interested. Bitmex server performance under load is disappointing, and now that the US authorities are digging into them, they are getting less attractive.
No I have been using US IP addresses all along and nothing bad happened. The response time has been fast for both desktop and app.
I think either they don't do anything special to US IP addresses, or they simply don't tag IP locations. My best guess is, as a China-based exchange, they might simply be less concerned about CFTC investigations.
Their engine is definitely strong. As for the interface, different people have different views. For me it took me time to get used to but once I got there, it turned out to be efficient.