[SPOILER ALERT] I liked it. It's got the goofiest plot of the 4 films, but I thought the action was a step above Last Crusade. Ford looks a lot older, but moves about the same and still packs a decent punch.
I loved the idea of the famed "Area 51" turning out to be the warehouse at the end of "Raiders," and the revelation that Indiana Jones himself lead the team that recovered the legendary UFO crash at Roswell. The whole alien thing really makes sense in Indy's anthropological universe, as there has always been plenty of non-scientific speculation that the Mayans and Egyptians couldn't have been so technologically advanced without a little bit of extraterrestrial assistance (anyone remember "In Search Of..."?).
Introducing Indy's son (and, like Indy, naming him after a dog) was as inspired as having Indy's father in Last Crusade, although I wanted the relationship-moments to be a bit more poignant like I felt the Indy and Henry Sr moments were. This also reminds me that I felt Karen Allen was a bit underutilized, serving more to bridge the gap between Indy and son rather than develop her own character. And what the heck was the point of John Hurt's character? Cate Blanchett was a bit less over-the-top than I thought she would be, but having Russians as villains was great as we haven't had a good Soviet baddie in a good 30 years since the Cold War ended. At the Russians expense, very nostalgic.