I was at the store the other day and I was looking at the thin seat pedestals. I've always had the old style 2-in thick ones. Are there any pros and cons to either?

If you look closely I think you will find that they are pretty much boat specific instead of age related.  My Nitro tales the thin ones while my buddies Phoenix takes the larger one.

Oh l didn't realize that

My Dad’s older boat used the 2” taper lock pedestals originally, I replaced them with the slide in 2” ones at some point. Those things were wobbly as a drunk skunk bc those bushings got so worn out so fast. Not to mention a pain in the rear. The slide in style was an improvement but still a sloppy interference fit. 
 

My Tracker has the threaded king pin bases and posts. So so so much more solid and stable despite the post being thinner. That deeper connection and threaded lock of the Kingpin just is superior for stability over the interference fit. 
 

The overall diameter of the post really makes no difference with as thick as the tube walls are and the stability of the post and base fit. At least not for seated fishing positions. If it’s a drivers seat pedestal on a very large high horsepower boat then that could be different. 

1 hour ago, kschultz76 said:

My Tracker has the threaded king pin bases and posts. So so so much more solid and stable despite the post being thinner. That deeper connection and threaded lock of the Kingpin just is superior for stability over the interference fit. 

My Ranger is the same. The thinner threaded posts are much easier to remove and install.

 

The Crestliner I grew up fishing in had the wider, shallower non-screw type and those things were a pain in the rear to move around.

I was just thinking about this yesterday.  My Alumacraft is on 2" slotted posts and I don't like it.  To move the main seats you have to squeeze a collar down at the base.  But, squeezing the collar hard enough while still having a good way to pull it out is a PITA.  I'm considering swapping bases.  Has anyone done that?  They look like there's one for one replacements to all the plates.  

I decided against both taper-locks and screw-ins when I built Bass Trek. Went with un-threaded Kingpin bases/posts...push in/pull out...easy-peasy.

 

  

 

The thinner ones are generally not rated for anything above 5 mph, and some of (not all) the thicker ones are ABYC speed rated. That may or may not make a difference to you.

I have the thin slide in in my boat and I usually remove the seat when I'm planing.  I take some big guys occasionally and it holds them fine.

What is ABYC?