Hi Guy,
I have a skywatcher 12" goto and am quite happy. I also have GSO 12" OTA for my new EQ8 and kind of wish i bought a SW OTA instead, collimating is WAY easier with the SW as far as I'm concerned. As for the goto function (although I could find targets fairly easy myself too), I find the tracking really handy and not having to worry about continually moving the tube to keep the object in view. Plus its easy to set up with a simple 2 star alignment.
The skywatcher goto also allows you to move the scope without losing its tracking position which is extra handy. and of course you don't need to use the goto function if you want to freestyle it.
if you can afford the goto, go for it. if its down to going 16" gotoless or 12" goto, thats a tough one, it might depend on if you plan on taking it with you places or where it will be stored as the 12" as you're probably aware is about as big as you can go without needing a step ladder. SW also does a 14" goto but i think the price is close to the 16" so you'd go with that anyway.
I don't know much about the other brands, i think the Orion models might be the same as SW.
here's my flickr page to my photos obtained with my SW 12" goto
http://www.flickr.com/photos/80336656@N07/ including a bit of deep space.
Best of luck
