I appears that the NX5 only shoots SD video at MPEG-2 which I feel (cannot confirm as I don't have the camera yet) will not mix well with my other DV material in terms of quality. If shoot at 720 or 1080 what would be the recommended frame rate that will look great when down converted to SD?
It looks the same as avi from other cameras, there is no quality difference. There are always differences when you mix video from different cameras, so there will always be a little difference, which can be adjusted in the editor. Things like tint, or gamma.
Since SD is only defined as 29.997 frames per second in the United States, (also called 60i) that would be the otpimum to shoot at in HD.
From my experience and research, IF YOU ARE EDITING WITH FINAL CUT PRO DO NOT SHOOT SD WITH THESE CAMERAS.
I can't explain the exact details, but FCP does not like the SD files the NX5U creates. I learned this only AFTER shooting 4 weddings in SD mode with the NX5Us and it took a lot extra time in post and DVD creation to try to make the footage acceptable. The interlacing is horendous and for some reason the export is not exactly 720x480. It gets compressed vertically a little. I can't explain it and I don't know why, just take my word for it.
If you have any other questions about it post back and I will do my best to help. If you're not using FCP then I don't think you need to worry about it.