This is a question I get asked a lot. It is better to always try to build more muscle because the more muscle you have, the more fat you will burn. It also speeds up your metabolism and makes you a fat burning machine.
If you are a cardio junkie force yourself to just warm up for 5 minutes then attack the weights or do body weight training. Later, reward yourself by doing your cardio after you have given your all to your weight training. The minimum amount to see muscle tone is 2 days a week, but I recommend 3. For example I do body weight training 2 times a week using the TRX and lift weights 2 days a week. Because men generally have more muscle than women, this is the reason why men lose weight so much faster. Become a fat burning machine and lift weights everyone!
Let me know if I can help you in anyway. I have strength and conditioning as well as body weight training classes using the TRX available. In addition, I do one on one sessions.