OK, first off, let me just say that I've seen posts out there on this topic but it's usually people trying to decide what to buy. I HAVE a 50D and I'm considering trading the body and a Sigma 10-20mm for a 5D with relatively low clicks (12k). Here's what I'm thinking... I moved up to the 50D a few months ago from the Rebel XT and I've been pretty happy with the results. Compared to the XT, the 50D has more bells and whistles, better IQ, higher ISO options, better controls, and the list goes on. But every time I look at shots from a 5D I'm just blown away. The bokeh is so creamy and the IQ just looks so much better...even when using the same lens on the 50D. Another much debated benefit of the 5D is noise at higher ISO. I personally think that the 5D performs much better at higher ISOs than the 50D. The 50D tends to get soft at higher ISOs even when the noise reduction is set to low. This is a big deal for me as I tend to shoot a lot in low light and I'm not a huge fan of flashes. I'll use them when I have to, but I prefer to work with natural light. What I plan to do with the camera... I don't have a specific "thing" that I shoot. I've done weddings and I would like to do more, but I usually spend most of my time on portraits, still life, landscapes and city life. I could pretty much glue my 50mm f/1.8 to my camera (definitely use it the most) but I plan on getting either the 135mm f/2L or the 70-200mm f/4L IS soon. Here are my concerns... The 5D is a few years older than the 50D which makes me worry about life expectancy. The 5Ds that I'm looking at have relatively low clicks, but the age of the camera does still worry me. The 5Ds AF system. I've read in several places that this is the biggest downfall of the 5D. I'm pretty happy with the 50Ds AF performance. Can anyone help me out on this one? Any thoughts? While I don't use all of the bells and whistles of the 50D, I like to know they are there if needed. Is there anyone out there that has both bodies or has owned both at one time that can share their experiences? Any thoughts would be appreciated. Thanks!