Quoted from ForceFlow:

As an outside observer, there certainly seems to be a lot more going on at TPF than Expo.
There's also a litany of complaints that seem to follow expo around every year. I can't say I've heard anything but positive things about TPF.
The big perks to expo are the Stern tour, some of the seminars, and a handful of rare/one-of-a-kind pins. The sheer number of reveals, homebrew pins, seminars, vendors, and other special showings at TPF seem to go beyond what is available at expo.
Expo seems to have been in decline for a long time, while TPF has been growing. TPF is more of an enthusiasts show, while expo is more of a trade show. Trade shows in general have been in decline for a while. Enthusiast shows have been growing, which has a lot to do with the passion of the show runners and attendees.

Quoted from frolic:

What seems to separate normal regional shows from being global events are the industry seminars and new games being shown as well as breaking news. That's what gets Pinside buzzing and elevates any show. TPF definitely rivals Expo in that regard now.

Quoted from CrazyLevi:

It does seem it's the premier show for manufacturers to premiere new games.
Not sure if a limited entry weird format tournament is worthy of being a circuit tournament though - those are supposed to be premier tournaments! Maybe they'll premiere a new format next time.
Premier.

Quoted from Mr68:

But that's a part of the problem. Expo has become mostly a one dimensional show for manufactures. Texas Pinball Festival has it all with a well rounded show and arguable one of the best free play areas in the country. (Texas collectors put us Colorado boys deep into second place. )
I'm guessing but attendance at TPF has to be much more people than Expo.
If I were CEO of one of the manufacturing company's, I'd change things up and begin targeting my new game release announcements at TPF and then follow up at Expo as a later show. Expo exists mostly out of tradition at this point.