it's not that it would be incompatible with pc gaming, it's just that you likely would not be able to tell the difference between that and an $8 zalman clipon - the reason being VoIP codecs.
in online gaming, bandwidth is always a constraint. and the compression codecs that vent, teamspeak, skype, etc. use all shave the bitrate down pretty damn low, so much so that it nullifies nearly any advantage you'd get using a better microphone.
the A40 is good - it's a shame they changed the model from the 2011 version, but the 2013 one is still solid, and the mixamp is good.
i havent tested that senn model but they generally make decent cans so I doubt you'd be disappointed with em. the 350s are really good i know
also the A50 is the big bro to the a40, and is really good for being a wireless model. the condenser mic is pretty clear. nice to see not all wireless headsets are junk. it's on sale every now and then but retail is a bit overpriced.
if your main exchanges will be online chat, you're just as good opting for a cheaper clip on mic like zalman zm1 ($8) and getting a really good pair of stereo headphones, such as the ATH-M50 or ATH-AD700. audio technica makes excellent midrange models with very precise, balanced soundstages. don't be fooled; a good stereo model will do you justice in gaming, even where positional audio is key.
A50:
http
/www.headset-ratings.com/astro-a50-wireless-headset-review/
ATH-M50:
http
/www.headset-ratings.com/audio-technica-ath-m50-professional-studio-headphones/
ATH-AD700:
http/reviews.cnet.com/headphones/audio-technica-ath-ad700/4505-7877_7-32749295.html
happy listening