I've used a few. I will evaluate them all at NAB and let you know which I go for. The main choices are:

http://www.aja.com/d10a.htm
http://www.vtx.co.uk/video/digiboxa2d.htm
http://www.ensembledesigns.com/produ...ghteye/be3.pdf
http://www.kramerelectronics.com/ind....asp?p=FC-7501
http://www.shootview.com/video_digit...ers.htm#ADC272
http://www.bal.co.uk/bboxalthome.html#ASVC