That's basically my question, on the V1U (or any HDV camera) does the AE Shift option do the same as, but with more control, the Backlight option?

I don't really use the auto settings on my cameras, but I think AE shift is pretty simple. It should just allow you to shift the exposure which camera automatically chooses either darker or lighter. I'm not completely sure what the backlight or spotlight function does since I've never used it, but suspect there's a little more going on than just shifting exposure up/down.

AE shift is much smarter than the backlight and spotlight controls - the camera is still controlling the iris but AE shift lets you fine-tune the exposure as the lighting contrast changes. I have this feature enabled on my Sony HC7 and I wish my Sony FX1 also had it.

I record stage shows with the FX1 and have to manage iris, zoom, focus and audio levels and cope with sudden changes in lighting so I sometimes leave the iris on auto, although I still get overexposed faces under spotlights even with the Spotlight feature enabled.

AE shift would let me quickly tweak the exposure occasionally while the camera takes care of major changes in light level.

AE shift is much smarter than the backlight and spotlight controls - the camera is still controlling the iris but AE shift lets you fine-tune the exposure as the lighting contrast changes. I have this feature enabled on my Sony HC7 and I wish my Sony FX1 also had it.

There is AE shift control on the Sony FX1 and Z1U in the Picture Profile settings. At a friend's suggestion I've set my six picture profiles to have the same basic settings with just the amount of AE varying between them, starting with no AE on the first profile up to +3 for the fourth one, then -1 and -2 on profiles 5 and 6. If you haven't experimented with the picture profiles yet, check 'em out.