I'm seriously thinking about forgetting the whole Lion/Mountain Lion idea, and just staying with Snow Leopard as my main OS over the next couple of years. My computers seem to like it, and it's clean and stable.
I'm wondering, though, whether SL will be supported enough to be okay to use, once Mountain Lion comes out. Does anyone have any idea how well the older OS'es hold up after the newer ones are released?
Your perceptions are quite accurate. On the one hand I absolutely love the ease with which I can navigate among applications and the ability to arrange my work. Safari and Mail have had many significant improvements. I love full screen apps and the way the much of the user interface has become more subdued. Anything superfluous has been relegated to the background. Scrollbars disappear when they're not needed. Without scrollbars the "proper" scrolling direction becomes opposite from what it used to be, and astonishingly obvious. (You can reverse this if you can't adjust to it.)
Apple's stalwart programs such as Preview or TextEdit have had interesting improvements that hint at Apple's current philosophy, and will rock your world. For example, the simple task of periodically "saving" a document as you work on it is gone! For a long time computer user this is initially disturbing but after a while you get used to it. It is another example of not having to burden the user with mundane tasks, and that's the direction in which Apple seems to be going. There are many examples of this. For an in-depth review of this and many "under the hood" changes Google the Ars Technica Lion review that came out last summer. It's fascinating.
Everything is generally the opposite of Windows, in which windows seem to metastasize; popups and verbose alerts and bubbles are constantly appearing and the OS generally gets in my face. OS X has always been better, but Lion has become even more quiet in that regard.
On the other hand some of Lion's changes amount to so much eye candy - for example, the way a mail message swoops up and over when replying is distracting and needless. I don't like Address Book's new look, which is mere appearance devoid of any improved function. So yes, while you may perceive an iOS-inspired Fisher-Price mentality behind some of these changes, underneath it all everything you do with Snow Leopard you will still be able to do with Lion. Except Rosetta.
Which brings us to the one essential question:
... has anything pro from Snow Leopard improved with Lion?
Apps are still apps, and Lion really doesn't enable them to do anything they could not do before. However, Lion is as rock solid as Snow Leopard has been, and I prefer it. If you are averse to change you won't like it, but if there is one thing I have learned in my 27 years of using Apple products, it's that you must be willing to leave the past behind. Progress has been rocky in the past - I detested OS X initially - but things gradually improve and eventually become better, radically so.
I wish I could say the same for Apple Support Communities - this forum used to be so much more intelligent and polite. It's not much of a forum any more, and civility is pretty much gone.