Been off my Tri bike for nearly 3 years...

And I just signed up for Outlaw 2018??
(UK non WTC 140.6)
I have been doing some S/B/R and plenty of bike commuting but my immediate concern is my butt!
I ride a Brooks B17 on my gravel bike/commuter and just sitting on my Fizik Arione Tri 2 tonight, it seems ridiculous.

So, school me on what’s moved on in 5 years of seat technology (since buying the Fizik) and what are people riding for comfort in full distance Tri’s these days?