I sacrificed everything in my first "good" Sac event and don't regret it.
I am enjoying the event challenges to earn Lost Soul frags.
1) learning more about ways to apply specific effects/running teams I wouldn't normally use, and 2) doing so while grinding for resources I needed anyway
One gripe: I maintain that Nightmares are the worst-performing talisman in the game--they rarely ever apply any effect. I've been running Phantom Ed on a team with 2 sets of Nightmare+Advantage, all day long, and Sleep/Perfect Sleep is still my lowest achievement. Just truly useless talismans with abysmal effectiveness. Other Talisman effects with equally stated chances completed their respective achievements hours ago.