All of the sites work pretty well, so it comes down to whatever feels most comfortable to you. But, I'd never pay a fee for any of this. There's just too much available free.
While I tend to agree I have no problem with paying Weather Underground 5 bucks or so a year for full access to their radar data 24/7. There it is not free ware but it uses free NWS radar data feeds and is very customizable to your needs. I have been using it for about 6 or 7 years now. There is no annual fee for program and I have paid for a major upgrade a few years ago and have had many many free upgrades too.