Thanks for the tag.
OP, as Idahoktm said there's a difference between "spacers". There's no issue at all with running a top hat spacer, the issue people typically have is with preload spacers. The difference is where they're installed. The top hats mount on top of the strut assembly, whereas the preload mounts inside the strut assembly.
The difference in the way they work is that the top hat essentially lengthens the strut assembly which raises the front end. The preload applies pressure to the spring, which forces the front end up. In doing so it also stiffens the ride because modern automotive springs are typically progressive rate. The initial force required to start compression is less, which yields a softer/smoother ride, but as the spring compresses more force is required to compress it. If you preload the spring you eliminate some/most of that early compression so the truck will ride rougher.
Top hat spacers don't effect spring rates because they don't change it at all. As a result you ride will be unchanged unless you change the tires to something stiffer because they absorb some road feel too.
With all the technical stuff out of the way.
I've run top hat spacers on my last 4 Rams with no issues at all. A few key things though is that you have to keep it reasonable. On the 3rd gen too tall would cause binding of the half shaft which resulted in "popping" on some trucks. That issue seems to have been resolved with the 4th and 5th gen though. The only concern I've read about on the 5th gen is that too tall will cause wear on the upper ball joint. By too tall, I'm referring to greater than 2.5". This is easily resolved by simply replacing the stock UCA with a set designed for the Mopar lift. Same dimensions, just a higher angle ball joint. This isn't really needed in most cases, but some people do it as a precaution.
As for longevity. I had a set on my 2007 for about 4 years before I swapped it for a taller lift. I had one on my 2012 the entire 2 years I owned it. I had on my 2014 for 4 years too. I've had one on my current Ram (2021) since last summer. On all of these, I've had no issues at all. That's why I keep going back to them. They're cheap, they're easy to install, and they don't harshen your ride.
To be completely fair, they may not be the best option of you are looking to do extreme off-roading. That's mainly because it's just a stock suspension, and extreme off-roaders typically want something that performs better than stock. If you're looking mostly for appearance, and only use your tuck off road in a manner that the stock suspension is fine for, this is the way to go.
2007 Big Horn with 2" leveling kit on 33's:
View attachment 121407
2012 Outdoorsman with 1.5" leveling kit on 32's:
View attachment 121408
2014 Sport with 2" leveling kit and 1.5" body lift on 35's:
View attachment 121409
2021 Big Horn with 2.5" front 1.5" rear on 33's:
View attachment 121411
It's safe to say I like them.... Rams and leveling spacers, that is.