Yes I upgraded to Sierra from the os before Yosemite, I didn't fancy Yosemite due to all the negative reviews.
No problems at all to download or install but it did take quite a time as I am on the end of a lot of cable, Superfast hasn't got to Cornwall yet.
I downloaded it to keep my computer up to date and hopefully more secure if the blurb is to be believed. [size=78%]Only minor problem being finding the update for my printer driver but all sorted now. [/size]
Is it better - I didn't notice any major changes but the icons are prettier. It does try to integrate iTunes and some other bits like that but I ignore it and it isn't persistent about doing it.