I've found they differ.

First I tried the Morpheus from the Urology Health Store which was a total waste of money. There are several disclaimers in the manual that say things like if you press the buttons too hard you can invalidate the warranty.
The store was unable to tell me what the included lube which caused me a lot of irritation contained and also has a strict no refund policy. I would avoid both them and any of the devices they sell.

After that I went to the local smut store and after talking to the clerk a bit bought one there named Pumped by Shots, for about a quarter the price that works. It was amusing because the clerk was ~40+ years younger than me and talked to me in that slow patient way younger people sometimes do because they think you're really old.
I have since bought a third device called a Hydromax that uses water not air which is much better but has the downside of needing to be used in the bath. The advantage though is that it does not hurt. For me the air based pumps cause discomfort then pain after 10-15 minutes or so.

My experience with all the pumps I've tried is that they cause some engorgement but not an erection.
Trying any constriction device after pumping to maintain the engorgement I find extremely painful and I've stopped trying them.
I had the robotic nerve sparing surgery ~9 months ago and since have had zero problems with incontinence,
no erections, no desire for sex, and no orgasm because I just can't be bothered.