It's very apparent on all three albums. Some great examples to listen to are "Oh Love", "X-Kid", "99 Revolutions", or just about anything off of their 2012 trilogy of albums.

It's sounds like compression, maybe a super fast delay, maybe even some chorus, not sure. I'm going to be laying some vocals down very soon on a few songs and really like his vocal sound. Any tips or suggestions to try to get close? Even the backgound vocals seem to be mixed the same way, very apparent on "99 Revolutions".

I've been wondering this for a while now, and just had the idea to see if anyone around here knew what it was they were hearing.

Thanks!

99 was jamming. Loved the guitar tone too.

I think you are pretty much right on the mark.

Compression and a fast mild echo. I also think there's a small room verb on it. It has a right in your face, small room, ambience to it. None of the fx used are used excessively or in a heavy handed manner.

The choruses are layered with tight harmony and very likely doubling since it sounds so much fatter. The doubling would account for the "chorus" effect you mentioned.

Very few people intentionally put a chorus FX on the vocals. Not saying it isn't done, just that very few really use that. You get a similar, fairly pleasing, chorusing effect naturally, from layering multiple takes of the same vocal line that are actually sung vs cloned.

IMO
Compression, doubling, short reverb, all with a low cut first.
The low never gets there to muddy things up, so they have clarity and can be 'pushed' more through the rest of the signal chain.
Just my opinion