I've had both. I used to always use my HM for every ride. They're very comfy and well padded, but very thick and take a lot of getting used to! I felt perched at first.
Then I invested in *coughs* two (!) acavallo seat savers. Both gel out, one standard and one comfort ride. I LOVE these. I have one on both my GP saddles. Had my dressage saddle fitted my 4yo I would've invested in a black one too. They come up a lot on eBay cheaper than full price. They're less chunky than the HM ones, but just as comfy. I do everything in mine. Definitely worth every penny.
I've sold all but one of my HM ones now, and I'm planning on selling the last one (kept it in case the acavallo didn't fit on my treeless).