The only Land Rover I have owned was a Discovery II.
I currently own a Vanagon.
My particular van is not a Syncro but I have done a lot of research on the Syncro and the 2WD versions share a lot of parts.
The main issue that I think plagues both of these vehicles is lack of maintenance.
Neither is a vehicle that you can neglect and expect to work reliably.
With that said, Here is my opinion.
I tend to think the Vanagon is way more useful, way more reliable and a hell of a lot easier to fix.
After my Land Rover experience I no longer have a place in my heart for the Land Rover.
The concept is sound; durable suspension, capable off road, good size for tighter trails, Stylish (if you care about that sort of thing) and it has what is arguably the best transfer case ever produced in the history of transfer cases. (the locking models anyway.. Make sure you get one with a locking transfer case if you get one)
However Land Rover tried to cram all this electronic doohickery into the Disco II all while trying to use leftover bits and and spend zero dollars to keep their company alive.
I Rambled on on the land rover forums that Land Rover should be ashamed of themselves for ever making the Disco II available to the public.
Like most things, I researched a bunch before I bought my Disco and, being an ASE certified tech, I figured I could do the work and get it all tip top.
I found what I thought was a good one and made the leap.
It ran all of about a month before the first repair that set me back $600 in parts.
I fixed that and drove for another month before the next repair that set me back another $450.
I knew they were maintenance queens but jesus I thought I might get 6 months out of it between repairs.
Finally, after the dreaded land rover head gasket failure that occurred simultaneously with an oil pressure sending unit failure that sprayed oil all over the engine bay I had had enough.
I sold it for 25% of what I paid for it and have never looked back.
So, as I mentioned the Vanagons are a lot less complicated hence a lot easier to fix.
Every thing on the Disco seemed needlessly complicated.
Vanagons are also a lot more efficient in their design.
They make the best use of space and eliminate the need for a trailer or rooftop tent or anything else for that matter.
Even if you don't want a full on camper model you can put the rear seat/bed in one of the passenger models and have a plain old van for whatever use.
Then when it comes time to hit the trail you're practically driving your hotel so there is no need to bring a tent or any of that garbage.
The Vanagon does have a few disadvantages.
The heater system seems pretty complicated and does not work all that great.
Also if you plan on rock crawling, a Syncro is not the thing for you.
The overhangs and lack of suspension travel can limit them in some instances.
Lastly, you obviously can't buy a new syncro or even a 20 year old Syncro.
Most that you find, unless you are buying a fully restored $80,000 version, will need some work to get them back into shape and back to a reliable state.
I have been a VW guy since 1993 so maybe I am a little biased but I would be real careful about any Land Rover you may look at.
Spend a little extra up front and make sure it has maintenance records.
However, that is no guarantee that the head gasket will not fail 3 days after you buy it.