How well does the Apple Magic Trackpad perform as a mouse replacement? I'm planning to replace my mouse entirely with the Apple Magic Trackpad on my desktop Mac. My work involves lots of typing (both code and prose). I also use Aperture quite a bit for processing photos. I don't play games; other than chess (Yes, it's that sad.)

Is the Apple Magic Trackpad capable of totally replacing the mouse?
How does its ergonomics compare to let's say the Apple Magic Mouse? Better or worse for the wrist.
Is it accurate enough for touching up photos with Aperture?
Thanks.
I've found the trackpad to be great for general purpose use (particularly the 3-finger swipe-to-drag gesture and the wonderful inertial scrolling) but I've found it too inaccurate for GUI development work. 

When I'm laying out screens for software development, or creating graphics for said software, it's too awkward to exactly position things with. I suspect you will find a similar problem if you are touching-up images etc.

I've found the ergonomics to be good, to be honest - I mostly use the Magic Trackpad and when that's not suitable for a job (see above) I switch to a Magic Mouse for a couple of hours. I have relatively small hands and find the Magic Mouse to be a really comfortable mouse, with no strain on fingers or wrist even after prolonged use. The trackpad gives you less to 'lean on' but I haven't found myself with any wrist ache or strain even when I've been using it solid for a day, etc.