Videomaker – Learn video production and editing, camera reviews › Forums › Cameras and Camcorders › Professional Camcorders › What camera would you suggest? › There really isn’t much
There really isn't much difference between NXCAMs and XDCAMs nowadays. As far as I can see looking specs wise, NXCAM has more options for recording in AVCHD codec than XDCAM so unless you are very reliant on recording to AVCHD, then I would just choose whichever camera gives the most bang for the buck!
Camera wise, while the AG-AC90 is not a bad camera, you would probably do yourself a favor if you looked more at the AG-UX90. Much better sensor, pictures look great, and there is a general upgrade in specs from the other camera, around same list price. Like Paulears said you can get a really nice price on it, but you get what you pay for too.
The NX5R is a great camera and you should get good images on it. Just make sure that the codecs fit your workflow.
As for the X70, it is a compact camcorder (handicam for all intents and purposes). It gives great images but lacks an Iris and zoom ring. I would probably go for the new Z90 (check out Doug Jensen's youtube for footage) as it is an upgrade over the X70. It gives great images and the form factor is small making it easy enough to carry anywhere. It will give you professional results, and costs bout as much as the other cameras.