Is KEEPVID a Good Alternative to Download Helper

I've used Download Helper for years, suddenly there seems to be some issues with it.  Are there any free alternatives, perhaps something that can be used with Windows Explorer to download Tutorials off of YouTube.  I'm wondering about KEEPVID.com Are sites like this risky or even legal.  Or is it possible to download these type videos with WMP or RealPlayer.

Thanks

why not use Allavsoft which has both Mac and Windows version.

it can download video from almost all the video sites like youtube, vevo, ehow, Break, FunnyOrDie, blip.tv, redtube, youporn, porntube, youjizz, tube8, BBC, CBS, NBC, YouTube, VEVO, Hulu and Hulu Plus, Facebook, Yahoo Video, VH1, ESPN, WatTV, Videojug, Pandora, Myspace, Imeem, Google Video, MetaCafe, DailyMotion, Vimeo,  MTV and etc

it can directly download video to MP4, AVI, WMV, MKV, FLV, 3GP, MPG, DV, RMVB and etc.

it can also download video to MP3, WAV, WMA, M4A, RA, DTS and etc.