I use Ubuntu for daily web browsing and it has always automatically updated Flash. I can't remember how I installed it however; might have been via the "Additional Drivers" icon. Ubuntu automatically updates itself very often, i.e. several times a week.
The underlying Linux (i.e. command line) is obtuse in the extreme (grep awk cat blorp etc.; the simple Linux Bible I bought is 816 pages and weighs 3 lbs) but if all you want to do is browse, check email, and run software it's pretty much just like Windows, you just click an icon on the desktop (i.e. with Ubuntu the Launcher toolbar on the left) and go. Ubuntu even comes with substitutes for Word, Excel, and Powerpoint that I have found to work just fine with my previous files. Through the repository I also added Gimp (photo and bitmap editing), Inkscape (vector graphics), Blender (3D modeling and rendering), Audacity (sound editing), Qsynth (MIDI), and Stellarium (planetarium software) all for free. Well, not free for me exactly since I donated $120, but then you don't have to donate anything.