I'm going to assume you're using this for internal penetration/security testing, and not doing illegal things like breaking into others' networks.
In terms of 'better', it usually just boils down to whether a particular driver can do injection or not. If the native driver can inject with your card, then it's sufficient. If it can't, then try the madwifi-ng driver. If that driver can't either, then it doesn't really matter which you use, assuming both can monitor all frames being sent wirelessly. If the native driver won't even let you put the card into promiscuous mode, then try the madwifi-ng.
In any case, if you can't use injection, then you will not be able to fully test your network and you should purchase an Atheros or other model USB card which is fully supported by its drivers.