Looking at the prospect of flying professionally I spoke with other career pilots and they told me about LightSPEED. I had flown using a Bose set before, and the Sierra set felt just as good for me. I am incredibly pleased and now four years later have never had the slightest glitch. Totally worth it for me.
I have used other "cheap" sets and they put a substantial amount of pressure on my head to provide noise reduction and also felt much heavier. I have not had any issues of fatigue while flying long XC flights. I have used the Bluetooth feature as well as the 3.5mm jack quite a bit with no issues. I can't say enough good about them.
The only thing is I use a different case to keep them in as I was concerned that the case they come with might not protect them well enough. Battery life seams to be a little over 50 hours from what I have seen (just an FYI).
They present a very professional look, without the "top shelf" price tag (which is a nice bonus when your professional image is important).
Lastly, every time I make a radio call it is nice and clear, and most important I can hear every call very clearly. It is so nice not having to either repeat myself, or asking ATC to repeat themselves. Aside from all the features, that is what is number one for me.