I kind of going through the same type of agonizing of which switch to make.
for me it's a bit differernt - i;m finally going to make the difference from film to digital.
I've been shooting with a 1v HS and Elan 7N as a backup.
Shoot mainly landscape and weddings, with a lot invested in canon - 1vHS, Elan 7n, 16-35 2.8L, 70-200 f2.8L IS, 2 580EX, 1 420 EX, ST-E2 and had the 24-70 f2.8L, which i just sold a few weeks ago in anticipation of purchasing the 24-105 F4L.
I waited during the last 1 1/2 for a "affordable" full frame and was very pleased when i heard about the 5D. Sounded just like what i was waiting for. Then this Fall i went on a three week tour of arizona, utah, wyoming, shooting around 80 rolls of film. based on the cost of film/processing and discussions with other photogrpahers in the USA that I met shooting with the 1DsII, D2X and the 5D (ran into someone in Page who had just had the camera for a week), I realized that now was the time to go digital.
After getting back home, i did some more research on the 5D and became very dissapointed - i thought it would be at least have been as weahter sealed as the EOS 3 was. but even more importantly, i couldn't believe that canon released a camera that costs $4300CDN (btw, the price in canada has dropped all of $30 at one store), that did not have the same viewfidner exposure information as the 1 series cameras (the EOS 3 did have this feature). Moreover, the camera also does not have dedicated FEL. THe FEL feature was for me was the strongest feature of Canon's flash system. I also shoot weddings, and for me the FEL reading, used with the FE compensation was a deadly accurate way of metering at weddings with my 1v. This solves the problem of having black suits/tuxedos or white dresses throwing off the meter - and yes - i shoot almost every shot at a wedding using spot metering and the FEL, to ensure accurate exposure.
Let me qualify the statement of no FEL on the 5D. with my 1v, i use custom function 4 set to "1", which activates AF with the AE lock button, to seperate AF operation from the shutter release. THis allows me to pre-focus and wait for that right moment to take the photo. Problem with non 1-series EOS cameras is that if you set custom functio 4 to "1", you CANNOT use FEL!!!!! Incredibly STUPID design, and very important feature missing on a camera $4300!!
Not being able to afford the EOS1dSII, my first reaction was that i ran into so many happy Nikon D2x users that i started considering that as an option, but having so much invested in canon, the cost of making such a switch (taking losses on lenses/flashes, and replacing with nikon lenses and flashes), would probaby be close to spending the extra money and getting a 1dsII.
Then Nikon announced/leaked the D200. and since then i have again been toying of making the switch. I could get two D200's for the cost of a EOS 5D.
Morevoer, i like the ultra wide options that nikon has. I have heard good things about their metering and flash system, but am very comfortable with ETTL (Used to hate ATTL that preceded it), and for me the entire effectiveness of ETTL rests with FEL - which is not available to me with the 5D based on my shooting preferences.
The negative to me about nikon is their customer service. I switched from Nikon to Canon around 15(??) years ago, when i bought a F801, which i had for 7 months (actually 3, coz nikon had it for four months for 4 different repair jobs - the first 3 days after buying the camera - discovered hot shoe didn't work, and then the camera would just shutdown). anyways, after nikon on four separate occasion refused to exchange a brand new camera and insisted on repairing it, i switched to canon. With canon, being a CPS member, i dropped a 80-200F2.8L lens at a base ballgame - entirely my fault, and canon gave me a loaner at no cost, coz they didn't have a replacement mount for the lens in stock. so i am a little hesitant on wanting to take a chance on nikon customer service again.
Because of my negative nikon experience in the past, i decided to investigate gettinga 1dIIN - best compromise in my eyes between cropped sensor and full frame (1.3x sensor). I don't need the 8.2fps, like the weather sealing and the fact that it operates and feels a lot like 1v HS. most people call it strictly a photojournaltist/sports camera, not really suited for weddings or landscape - but then my 1v HS shot off 10FPS and i used it mainly for landscape and weddings (havnet shot sports in the last 4 years). i figure my 16-35mm will get me down to around 21mm wide, and i've also looked at getting the sigma 10-22mm which works with full frame, and that would get me to just under 16mm wide as an ultra wide option (have read mixed reviews about this lens, so not sure yet about how viable an option it really would be).
Right now, before i commit either way i'm waiting for two things - selling my 1vHS and the release of the 24-105L before making up my mind.
One question i do have is how much of a resolution difference is there between the 1DIIN and the 5D?? What would be the largest print possible with the IDIIN?? How does that compare with the 5D, D200 and the D2X???
would appreciate some advice on difference in noise, dynamic range, image quality between the 1DIIN, 5D, D2X and the D200, as well as how much a diff there is on how large of high quality prints are possible with these cameras.
If there was a signfiicant drop in price in the USA in canada for the 5D or the 1dIIN, i would probalby stay with canon, but i can;t see tha happening for a while.