I have been using Lion for a few weeks now, and have been fairly happy with it. Enjoying the new gestures, mail is not the great saviour I was expecting however. Its not bad, its a definite improvement, mail just got bigged up rather a lot. Im still getting used to using gestures instead of hot corners. Im a bit clumsy at the moment, but think it will speed up my work flow in the long run with less accidental hot corner activations. The main reason I upgraded was for the under the hood security upgrades, these were significant and worth the £21 alone. Photoshop CS3 worked fine, which was a surprise.
The built in word define tool is great for a luddite like me
Not really noticed full screen much as Aperture was full screen anyway. Thought I would disable launchpad, but I find it has really sped up my App launching. Auto save is taking some getting used to. When I invoice people, I usually open up the last invoice and change date and costs etc so I don't need to re entire tonnes of info. I keep forgetting to duplicate the invoice before editing and over writing. Not a big deal, as versions makes it easy to roll back, but a pain none the less. Once I have adapted I can see Auto Save and Versions being features I cant live without. I can only dream about the day Adobe enable Photoshop to work with Versions, but that wont happen for a long long time from experience…
A few days ago I reinstalled from scratch so I could setup a raid array. Ive noticed drastic speed increases over the upgrade, but as I'm a particularly messy Mac user (and I have a pair of striped 7200rpm drives in my MBP now) your milage may vary. I have succesfully staved off upgraditus for another year, as long as the fabled 15" MacBook Air does not show up