We stayed at The Jockey Club for a week in October 2009. We were lucky and got a suite on the 11th floor, facing The Bellagio, so we had a great view, unlike all the people on the other side of the complex. The suites are very spacious, if a little dated, and have everything you could possibly need. The location is great, and the staff are friendly and helpful (apart from the concierge guy we spoke to). Free Internet is a nice touch too, helpful if you need to check emails, check in for flights etc. The Mini market on site is reasonably priced and stocks a good selection of basics, we used it for drinks and snacks.
The major problem the Jockey Club has, as others has said, is all the construction. The noise didn't really affect us, but we were very dissapointed that the pool area gets no sun at all now thanks to the massive buildings that have been built right behind it, and even on a hot Vegas day, the pool area can feel quite chilly. My In-laws were amazed when we showed them the pictures, as they remember the Jockey Club how it used to be before the construction started. The pool situation was overcome by asking at the front desk if there was another pool I could use to sunbathe. The Flamingo, about 10 minutes walk away lets non residents use their pool after 2pm, so I spent a couple of afternoons sunbathing over at their pool, not ideal, but better than the chilly Jockey Club pool!