I responded to their posting on a job board. A couple of weeks later one of their recruiters contacted me to request an in-person interview. We arranged for the interview to be a few days later.
At the interview the interviewer had me look at some C code on his Apple notebook and write the rest of the function. I would then have to compile and debug the code. I had a choice of either vi or emacs. I consider myself an avid emacs user (though, specifically XEmacs), but like most emacs users I've made numerous customizations to my environment which obviously are not on his computer. Moreso, the coding and debugging must be done from the command line. I've been developing in C++ in Unix environments for more than 14 years but this is not the 1980s - when I run gdb I do it in XEmacs or NetBeans, not directly from the command line.
About 30 minutes into the interview I frankly told the interviewer that it was obvious to me that I was not meeting his expectations. He agreed. He seemed quite smug about it.
Though, even aside from the archaic manner in which he expected me to prove my competence, I had already lost interest in the position as soon as I walked into the office and saw that it was one large room with a bunch of coders sitting at open tables. No cubicles, no desks, no privacy. It reminded me of a sweatshop or boilerroom.
The posting gives the impression that they're looking for C++ people, but it turns out almost all of the work is in C and Python. They also failed to mention that most of the work is done by ssh-ing into servers and working entirely from the command line. Had I know that I wouldn't have bothered with the interview.
At the end of the interview, I asked the interviewer whether many people actually complete the challenges successfully. He said "Oh, yes, many people do. Many smart developers finish both tests within 10 minutes." I wasn't sure if he was saying I wasn't smart; or was an incompetent developer.
Also, the interviewer's keyboard had a different layout (Mac) than the ones I've been using every day for the past 15 years (Unix/Sun) so I kept hitting the wrong keys. From that he inferred that I didn't know how to type.
I don't know that it's reasonable to try to determine the skill level of a senior software engineer by having him work through some fairly simple coding problems using only tools he's not familiar with and wouldn't actually have to use on the job (he told me some of the developers use Eclipse, or whatever environment they wish). If the interview tests are any indication then I think they're looking for coders, not engineers.