Linux is fine for bread an butter ie web/comms/ and office for an average user.
so 99% of computer uses
Stability wise, XP Pro rarely crashed, Vista hasn't-at all- and neither has my Win 7 laptop. It hasn't been my experience that Win is any less stable than Ubuntu.
I think windows instability does get overstated. However, all I can point to is my personal experience. I spend basically zero time doing system maintenance other than installing the updates as they show up, and my system hasn't degraded despite being on basically constantly without reboots (other than kernel updates).
As for security, I'm not convinced that Ubuntu is any more secure per se, just that less time and man hours is devoted to exploiting its holes. And there must be holes, else why are the security updates being released periodically for it?
Its not a question of whether there's holes. Its a question of what they compromise. There's plenty of articles explaining this in more detail than is reasonable for a forum post.
I don't particularly like the Ubuntu (Gnome and KDE 4) look and feel either, and I don't think its as fast and efficient as its claimed. I think its the Windows of the Linux world; people use it because other people use it.
Side by side on identical hardware, I can verify it runs far better than win 7 on my buddys netbook, and versus vista on my desktop. Obviously you can do faster and slicker elsewhere.
As far as the look, change it. Desktop environments can be exchanged. Try XFCE or fluxbox or ..or..or.
Its nice to have choices
