I have been reading a lot about Lion and it seems to get mixed reviews. Are you all as devs happy with the upgrade? If yes/no why?
For my day to day (Rails and iOS programming) there isn't a huge difference in the two.
Obviously Lion has more UI changes than SL. There are some nice little things - lots more polish. I don't really use the Mission Control stuff on Lion nor the LaunchPad (gives it iOS app groups/paradigm).
One nice thing about Lion is restarting the machine. You can have it pin the apps on different desktops on startup and 'resume' where you left off. This also happens with Terminal - open a new tab and you're in the same dir as the previous tab.
Some disk access/app launching seems faster in Lion. Other than that, there's not a lot of stuff that feels different. I suppose you'll have to upgrade at some point just to not be 'left behind'.
But overall, imo, very similar experience.