In Thailand, the D70 with 18-70mm kit lens is around $1750 ($1299 retail in the US).
I will try to get comparison picture between C5050/D70 this weekend. I don't have any tripod though since 99.9% of pictures I take are underwater. On land, I have a lazy photographer syndrome!
Autofocus is definitely significantly faster with D70.
Oly RAW format (ORF) is 2560x1920 while Nikon RAW format (NEF) is 3008x2000 but ORF is about 7.1mb while NEF is around 5 mb so Nikon definitely uses quite a bit more compression with its RAW file. There is no option for uncompressed RAW file like in Nikon D100. As a result, I can fit almost 200 pictures on 1 GB card with D70. Also the proprietary battery on D70 is supposed to be good for well over a thousand pictures so look like I won't have to open the housing too often when I am on the boat (except for changing lenses/ports).
Writing speed is significantly better with D70 as well. With Transcend 45X CF card, C5050 takes about 4 second to write each picture. Its buffer will hold 3 RAW pics (in sequential mode) then I would have to stop and wait quite awhile before I can shoot again. D70 buffer will hold 4 NEF (shoot at 3fps) then after the buffer is full, I can still keep on shooting in sequential mode at about 1 fps smoothly. May not be great for land photography but it is about the right amount of interval for my Ikelite strobe to recycle as well.
There is no delay when I shoot picture one at a time, just shoot, recompose, adjust whatever then I can shoot again right away unlike the Oly 5050 where the LCD monitor would freeze until it finishes writing file to CF card before I can use the LCD to compose again.
Nikon View 6.2.1 is significantly better than Camedia that came with Oly 5050, as far as using it to view RAW file, the layout is better thoughtout.
There is no noticeable shutterlag like the C5050 either.
I really like the camera so far but unfortunately Ikelite does not support the 70-180mm macro lens that I want to use so choices for housing will be quite expensive. I think I will have to sell one of my kidney to finance my new baby!