I Never Tested the CM Sirus? So cant give any opinion. But i had compared the G35 with Razer Megaloden. I would say Logitech G35 will all the round over the Razer Megaloden except the The comfort (You cant wear G35 for more than 3-4 Hours). Razer Megalaoden will win only in the Comfort level. Other than that Logitech G35 will be KICKASS product.