The new UI and quality of life changes are great; I like playing the game without so much eye strain. Adventure mode isn't available (yet).
For those new to the game, have Fun! The dwarf fortress wiki is a great resource, but it isn't currently updated for the new steam edition details. Aside from the UI changes, the differences are generally minor. Quick start guide recommended. The steam edition also has a built in tutorial.
Just picked it up myself, hopefully get a chance to play it sometime this week. Was going to give the old version a try, but I figured new graphics would make figuring this out easier.