Saturday is just as good a days Thursday or Friday, but does get crowded. The size and quality of the free game room is open to your perspective of where you have the ability to play currently. The chance to play tons of great 80s games, and a bunch of EMS as well as 90s era B/W and newer Sterns is not something everyone gets the opportunity to play. For the anniversary a few years ago, there were a ton more machines that normal, and they needed an overflow room, but as I said, plenty of games to play.
Rumor is JJP will show Pirates, I assume Stern/Marco will have SW, which most folks have not played yet. There will be mulitple Houdini machines there, and I'm sure CC will have AFMr. TNA can be played out at Pinball Life if that is high on your list and it is always a fun time out there (but may be sold out). And there is the chance to tour Stern, not something you can do at other shows. So despite the naysayers, anyone who goes to Expo is going to have a good time, especially if you take the time to meet people.
The fact that P3 and the p-roc custom games won't be there is unfortunate, since I know that is something a lot of folks enjoy.
So, while for many Expo does not live up to its past, and I'm not going to say that is not true. It is still a fun show with some really interesting seminars, the latest info from manufactures, and more industry folks and other personalities then you will see at other shows.
Is Expo better than TPF, not sure, they are both great shows, and for any real pinball fan, you should try to get to both at some point. Not saying that places like allentown, MGC, SFGE, NW, etc. are not worth going to, they absolutely are, since each of those has their own personality. I know a few guys who will say Allentown is there favorite show, since it is a great place to buy and sell. SFGE and MGC are great shows if you like the spectacle of 'gaming' vs just pinball.