By 'event' do you mean the dining packages for Rivers of Light (Tusker House) and Fantasmic (Mama Melrose or Hollywood & Vine)?
We have yet to see Rivers of Light, but will in two weeks!! It is getting decent reviews (not Wishes awesome but worth seeing once). Fantasmic! is a must see for us every trip.
If you choose quality food over character interactions, then Mama Melrose would probably be your safest bet. Tusker House was one of our least favorite meals. I would put H&V way over TH in terms of both quality of food and character interactions, but others disagree. Regardless, both are character buffets so set expectations accordingly. If you are planning to eat at one of these restaurants anyway, then you might as well book it as the dining package since the only difference for you will be paying a bit more on tip. If you are choosing one, I would definitely choose the Fantasmic package. ROL is only a Tier 2 (non-Pandora) FP while Fantasmic is a Tier 1 (ie- no RnR or TSMM!) As for standby, I know Fantasmic! will fill up early because we are traveling at peak times but they are only offering one show per night (thanks Disney!) vs. the 3 showings of Rivers of Light.