A couple disclaimers: I am not going to go into the technical aspects of the cameras. There are plenty of articles on the web that a simple Google search will find. Additionally, I shoot with a Canon 50D. It is not full frame, but it suits my needs. So, I am going to approach this side by side as more of an artistic and personal experience endeavor. I am by no means an equipment tester. This was purely for fun and to satisfy my own curiosity.
My first impressions with the Sony were that it felt plasticky. I am used to my Canon and love the rubbery feel of the body and the heft. That heft gives me the peace of mind that this is a rugged piece of equipment. In addition, the heft helps me hold my camera steady. With lighter weight cameras I feel like I'm flinging the thing around. However, the light weight of the Sony can also be a benefit. When traveling, I tend to grumble a bit when I know I'm going to carry around heavy gear. So here is a nice camera, that's light-weight so it would be nice on vacations.
The Sony has an electronic view finder. I am not a fan of EVF. I prefer to have the live view of my Canon. However, there are a few neat features about an EVF. You can zoom into the image to ensure tack sharp focus. Additionally, you can turn on a leveling feature to ensure your horizon line isn't kittywampus. One other nice features with the EVF is that you can have the histogram appear in the viewfinder. That way you don't have to halt the session to look at the back of the camera's LCD screen.
The Sony shoots warmer than the Canon. The Canon 50D has a reputation for shooting cooler. I have customized my white balance accordingly and because I shoot in a fashion inspired style, cooler images are perfectly acceptably to me.
A concern with switching to Sony would be the availability of third-party products. Currently, Canon and Nikon are the big players in dSLRs so third-party vendors cater to the two. Also, in order to attach my flash trigger to the hot shoe, I had to use an adapter because the Sony does not have a standard sized hot shoe.
I recommend viewing Matthew Jordan Smith's work in order to see a photographer at the top of the profession who shoots with Sony.
As for image quality, my friend is correct. The Sony stands up very well with image quality. Below is a side-by-side image from the two different cameras. The image created with the Sony a65 on the left. The image created with the Canon 50D on the right.