A susupended seatpost is not really a good idea for a road bike unless you are tired of the bumpy ride on rough roads of the city. I have one on my touring bike which I really like, because I use it to ride the mtb trails near where I live.

I borrowed a "post moderne" from my neighbor for trial. Here's my review:

Pro - Really takes the edge off little bumps. So less energy transmitted to your tender bits. I was able to ride unpadded shorts with the suspension post, something i wouldn't be able to do on a rigid post. I was able to simply ride over obstacles that i previously steered around or went out of saddle for. So the thing does work pretty good for intended purpose. Very careful adjustment to spring compression is required for optimum benefit.

Con - Impossible to tune out the pogo effect, which is experienced at higher cadence. These posts are simple devices compared to front shocks, and there's no way to dampen the rebound from the post (at least the one i tried). Also, the post is necessarily heavy compared to rigid post. Say 550g vs. 200g on a light post. I think the pogo effect would make this post highly undesirable on a road bike used for fast riding. The pogo would bounce you right off if you tried to hammer the pedals. Also, there is a small amount of lateral play in the post that can't be tuned out, which you think would be an issue; however i never actually noticed it when riding.

I think suspended posts are a good option for certain folks, for more casual riding. I think they may be a real plus for offroad use, but have no experience with them in this scenario.

I hope i can try a sprung saddle some day.

On my cross bike I use a suspension seatpost called nitropro which doesnt pogo at all. when i go over a bump i feel it compress but strangely it doesn't seem to reset itself until later. but it must somehow, because a minute later i feel it working again on another bump. i was curious if others had tried it too but surprisingly a search here on BF turned up nothing.
It's a pretty heavy post and it goes deep in the seat tube, but i've had back surgery so i think it's worth it for me.

My broken-in Brooks B17 does a very fine job absorbing those bumps. Due to the hammock effect, I think.