Hi all. I haven't worn a watch in forever, and haven't entirely been impressed to consider getting and Apple Watch before. However, with the updates I'm considering getting one, but totally confused by all the differences and cost structures! 
1) ceramic coating (in back) is better and less scratch resistant than the composite back? This is only available on cellular and higher models?
2) what is the difference between stainless steel and aluminum types?
3) Sapphire face is considered better and less scratch resistant...but only available on SS model or all cellular models? I couldn't tell from the comparison chart on Apple's site.
At $329 I'm down as an impulse buy, but if I really need to be looking in the $600 range then I'm a lot less inclined to get one.
Thanks for the help and clarification.

1) ceramic coating (in back) is better and less scratch resistant than the composite back? This is only available on cellular and higher models?
2) what is the difference between stainless steel and aluminum types?
3) Sapphire face is considered better and less scratch resistant...but only available on SS model or all cellular models? I couldn't tell from the comparison chart on Apple's site.
At $329 I'm down as an impulse buy, but if I really need to be looking in the $600 range then I'm a lot less inclined to get one.
Thanks for the help and clarification.