Here are a couple of great videos on some common audio recorder comparisons, as well as a look into mic polar patterns and best practices for recording audio with your HDSLR video. In the first video we get a look at the noise levels on the Zoom H4n, Tascam DT-100 MKII, Sound Devices 702, Beachtek DXA-SLR PRO, Edirol R44, Tascam DR-680 and the juicedLink Riggy Micro and Riggy Assist.
This is a great video to bookmark for reference given all of the mic comparisons within. Being a big fan of the Tascam DR-100 MKII, I was rather surprised at how well the juicedLink Riggy preamps performed when recorded direct to camera. They are obviously doing some good work over at juicedLink.
Next, take a look at this video with Olivia Speranza and Robert from juicedLink as he goes over some mic performance and behaviors, as well as other best practices when recording audio for video.