Provia 400X is hands down the go to slide film for when you need a couple of extra stops to capture available light photographs. The film has some very pleasing colors with a good amount of saturation, and produces great results even when push processed at EI 1600. The only downside is the price which combined with the cost of E6 processing can be a bit prohibitive, but the results are well worth it. Also, keep in mind that slide film typically has less latitude than color negative film which requires one to be a bit more careful when setting the exposure.
The roll I received from Amazon was fresh with plenty of time before the expiration date.