Is this worth the money?
Do the top producers show up from burgundy and bordeaux? Champagne?
It is worth the money IMO. The top Bordeaux producers show up, but there is no Burgundy and very little Champagne. What you will find in their absence, however, are some of the the best producers from Barolo and Tuscany.
Definitely worth it. A lot of very good to great producers from various areas (but not Burgundy and Champagne, for the most part). You can’t taste everything available, so try to use it as an opportunity to step out of your comfort zone. If you usually only drink wines from France, try things from Italy, Spain, Germany, Portugal, etc.
Agree with comments above in it being a worthwhile event. You can take a look at the participating wineries here:
Definitely worth it! 
Can/will be rather crowded, so my advise is to preplan which wines you want to taste and stick to the plan. Make sure to hit the top names first, in that they will often run out.
Spit!
Good earlier advise about stepping out side your comfort zone. A lot of terrific wines, and a great chance to introduce yourself to new wines, with absolutely no phlonk anywhere.
Definitely worth it, but plan to get there at least an hour early to line up to be first inside the venue.
Only done this once, so far. Aside from the line to get in, the event is very nice. Plus, it was nice to see so many owners/principals manning the tables, rather than just reps.
I’ve been twice. An excellent night both times. Can even be overwhelming. So much good juice!