An E&P system was already fitted to our MH which we bought second hand at a year old. Prior to that in my own mind I couldn't justify the cost despite hating going up on blocks. Now I wouldn't be without them! In fact when we sell this MH and get another, I'll get them taken off and put on the new MH. Total game changer for us.
One thing to bear on mind is that whilst they are great for 90% of times, they will only lift so high. You can correct this by carrying some flat wooden blocks which can be placed between to ground and the feet. These are also useful if on soft ground as they will help spread the weight. Ones came with 4 that were 16 inches square and around 3 inches deep which I cut down to 9 inches square as I thought them overkill at 16 inches. If you get/make some, attach a bit of rope to one corner so they are easier to retrieve and pull out of the ground if squashed in.
Also bear in mind that when on full lift (or even if higher using blocks) that the steps down from the MH are deeper so you may want to buy a decent folding 2 step to carry as well.