A solid sleeve - between the bearings, because that's where it sits - will require even MORE installation expertise.
So the (unproven.. really) increase in diff reliability vs the huge increase in installation error causing inreliability is IMO not worth it.
Sure, if you're an A+ installer (like S2KPUDDYDAD) with all the experience and tools, its not such a big deal to install a solid sleeve correctly.
The one-and-ONLY benefit of the solid sleeve is that you can tighten the pinion nut with more torque.

That's IT.

If you don't go cheap and get 1 (or maybe 2) new pinion nuts (so you can use a new one as soon as you have found the right shim) that new locking nut will not back out.
The crush sleeve design is 100% ok.

 

If you do plan on going the crush sleeve route,buy two of them just in case. There is a good chance you might over crush the first sleeve and you may need to start over and do it again. Especially if this is your first time doing it. I believe S2KPuddyDad sells an industrial strength sleeve that is stronger then the factory one if your interested. At least with the solid sleeve setup ,although more expensive, you dont have to worry about over crushing it like the standard crush sleeve.

 

You can not overcrush the sleeve.
The sleeve can never be crused more than the distance between the pinion bearings.
Once the distance between the bearings is at its minimum (*) you can not crush the sleeve any more, if you try you will destroy the bearings.
The sleeve is like a very strong spring, and eventhough it is not made of spring steel, when crushed to a certain point ( the point marked by (*)) it will bounce back a tiny little bit when released.
You should not re-use a sleeve as replacing parts may change the distances between bearings enough to make the used sleeve just a bit too short.
The not re-use comment sounds contradictive with the overcrush comment, but as taking the diff apart usually means that parts are changed the sleeve should be replaced too.
To find the correct shim when installing new gears you don't even need a sleeve between bearings anyway.

The name "crush sleeve" is IMO the start of many misconceptions.
Crushing is bad... mmkay.. don't do that.... mmmkay...?

Many think that launching the car will "crush the sleeve"

So "When I drive my car hard y'know.. I need something better y'know.. because I drive my car HARD... y'know..."
And that's not that case.
There is not load on the sleeve when driving, it just sits there between the bearings and does nothing more than provide some backpressure for the locking nut.
The fact is it makes it easier to set the pinion bearing pre-load during the gear installation.
When a new locking nut is used at the final build (when the correct shim thickness is known) it works 100%.

 

If you are setting the pinion preload with a crush sleeve and you accidentally set your pinion preload to high,that crush sleeve is done.
They might have some spring in them,but not much.if you do a search on overcrushion a pinion sleeve, you will see it is definitely possible.