I've had a 53 since Jan of 22 and passed on my 63s that recently arrived since it was missing some key options like the high end burmester. Having spent an hour driving the 63s, launching it, and testing all the different modes I'm making a comparison for anyone who wants to know which one is the right one for them.

Gle 63S:
Pros:
Massive power difference (this feels like an amg, the 53 doesnt)
Immensely more comfortable and enjoyable to drive in (race mode is more comfortable than the 53s comfort mode) **53 with base suspension
Emotion start + any cracks pops, reving sounds much better
You have the top tier trim for bragging rights

Cons:
Lacks any real distinction or prestige from GLE's and even the 53 unless people know what to look for
You can get everything a 63s has minus the engine in a 53 for 30k less.
Suffers from the same clunky transmission issues GLE's have. Struggles to **** down to the right gear often 2 gears higher than needed. When you put your foot down there's a delay before you start going when already driving.

Gle53:
Pros:
Looks exactly the same as the 63s with dynamics plus package (even without most people can't tell a difference)
Massively less expensive
Better on gas
Can get every single option the 63s has here except the engine
Still fast enough for majority of people
Get the pops and crackles and all the "AMG" experience with the performance exhaust option
Handles amazing even with base suspension at high speeds (145mph+)

Cons:
Same clunky transmission as 63S that struggles to find the right gear
Base suspension is very bad for comfort
Slow slow slow, just starts pulling then the torque ends (should have 700NM-520ft-lbs to be there)
Comes with barely anything, you need to add a TON of options
Performance grows stale when you're out of honeymoon phase and realize you will lose 99% in street combat
Silver brakes suck and look bad too
Every option is more expensive than on a 63S
Fully loaded your at the starting price of a 63S



My Must Have Options for both:
High end burmester
Acoustic Comfort
Driver Assistance Package
AMG Performance Exhaust
Massage Seats
Heated & Ventilated
4 zone climate control
Surround view (ridiculous this isn't standard on GLEs)
Augmented Reality
AMG HUD
Rear side airbags

Conclusion:
The cars are extremely similar, aside from the massive performance when you push your foot down and much better comfort and racing feeling due to the upgraded suspension on the 63s, the cars are indistinguishable. This makes it down to one factor in my book. Do you care about driving fast and having a high performance suv? If you do then get the 63s, the 53 will disappoint you since the difference between the two is night and day. Otherwise you can get the 53 and load it up and still save yourself 30k since it's practically the exact same car minus the engine.

My recommendation is to wait for 2024 since even the 53 is getting a torque bump and both cars are getting more options as standard.