I don't have specific Sony experience, but I'd suggest getting over the doubts. There's a number of reasons for this:

1. Sony bought Minolta, a camera company, and thus bought into the Minolta legacy and their glass. In other words, your friend isn't correct, there is a lot of Minolta gear on the open market and much, if not all, will work on a Sony.

2. When it comes to second hand, legacy, gear the only company that will better Sony in support (and that may be debatable) is Pentax. Like Pentax, Sony has shake reduction on the body and that means old glass will benefit and there is some truly great optics out there for peanuts.

3. Sony is a massive corporation, you can get gear repaired by them, they're everywhere. Bear in mind that a dSLR is an electronic device and Sony is the king of electronics. Frankly I'd expect it to be easier to repair Sony, they have their own stores after all, the only camera maker that does. Besides, a close friend with a 7D got to spend more than 3 weeks with film when his 7D was in for repair with Canon, not exactly speed service there, so I wouldn't assume that you gain anything from Canon on this front.

4. Zeiss glass will equal or exceed lenses made by Canon. We're talking one of the best lens makers on the planet with Zeiss.

5. Sony makes more than 50% of the worlds sensors, including sensors for Nikon, Pentax, and others. Simply put, if you aren't shooting Canon, you're very likely shooting a Sony sensor. Does it mean anything? Well, cameras making the most buzz about things like high ISO with low noise carry a Sony sensor.

6. Like Canon, Sony has full frame options and they're very well priced and well reviewed.

Now, after all that, Canon makes an excellent camera beyond question. They have great lenses, strong support, and their image IQ doesn't give into others. So, if you do cave in and go Canon, I'm sure that you'll be happy with them. However, I think you'll also find that you really didn't gain anything over Sony with a comparable camera.

That's my take, in any case, and I'll be curious to see what others think. For myself, I can't believe I just defended Sony!

By the way, the question is subjective and that may get it shot down but I didn't vote for that because I think it's worthwhile to have people ask some of these questions. There's a weird brand loyalty in the camera world that goes a little beyond the rational sometimes and so it's worthwhile for us to have some discussions that maybe challenges those beliefs a little bit. After all, it's a photographic tool, not a life partner... :)