Hi, some BIG questions! I strongly advise, if you're a new horse owner or thinking of getting your first horse, that hoofcare, hoof health & function is one of subjects that you give precedence to studying for yourself. As with anything horsey, there are different opinions & levels of knowledge & understanding that go with those opinions, even among 'experts', including vets & farriers. And hoof health effects general health, soundness, as well as use of the animal. On that note, the thread link in my signature below is one good place to start.
Now for my opinion on your question... Yes, there are many differences between metal rims and something like Eponas or Easyshoes. I do believe there are more or less 'pros' & 'cons' between different styles of shoeing, depending on how they're applied, how healthy - or otherwise feet are when applied, what they're used for & on what surfaces.
Of primary effect, IMO is the peripheral loading effect of rim shoes, *where effective & appropriate padding isn't used* - whether metal or plastic - when on hard ground. Especially if hard, flat ground. The walls are forced into sole(pardon pun) weightbearing, and the soles & frogs are more or less(*well* shod, frogs aren't quite) out of commission. The extra force on the walls can strain laminae, allowing for easier distortion and put excess pressure on both the coronary & the circumflex arteries, reducing circulation. The lack of support under the foot can allow the inner foot to 'sink' in relation to the capsule - flatter soles but longer hoof capsules, P2/P3 joint inside the capsule. Lack of good use also allows soles to thin and frogs/caudal hoof to be/become weak - 'if you don't use it, you lose it' applies.
Something like Eponas or Easyshoes provide far more weight distribution, protection and support over the whole base of the foot, without the need of extra padding to do this. Rim shoes whether steel or plastic, without pads provide no support or protection for the base of the foot. **To be fair, bare or booted feet, unpadded, can indeed suffer from 'peripheral loading' too.
One thing that applies to metal but not as much to plastic, is the extra high frequency shock, when the shoe hits on hard surfaces. This has an effect on all tissue & joints, including further up the leg, when it's chronic. Still, depends what the material - hard plastic or rubber for eg - & how they're built as to how much shock dissipation they may have.
Unyielding material, firmly attached to the base of the foot, no matter how well, if it's constant pressure, will cause reduction in circulation and 'pressure sores' underneath. 'Corns' at the heel of shod horses are so common the heel corners are aka 'seat of corn'. Flexible material, which allows pressure against the sole on weightbearing, but which is relieved at every step doesn't cause that, but instead, like well functioning bare feet, enhances function/growth.
Eponas & Easyshoes also have quite extensive & flexible heel/frog support and heels can flex up & down independently. IME of Easyshoes actually seem to enhance heel stimulation greatly. I haven't personally experienced Eponas, but have been told they're pretty good on that too. I've noticed heels open up and become stronger with Easy's.
So I think that's about it, the major differences between metal &/or rims, v's Eponas, Easy's, bare feet....
Oh, grip & abrasion resistance - 2 areas where conventional tends to come out on top. Rims are better for grip in slippery(eg mud, clay, slick grass) than Easy's. Easy's are however, not so bad & way better for grip than boots in this way. Tho plastic/rubber is better on concrete/bitumen. Speed & jumping aren't overly great for boots, but fixed shoes, whether plastic or metal seem to be fine. And while boots live up to abrasion resistance in most 'normal' type situations, they may not be as good in some situations, such as long miles trotting on hard/rough ground for eg. Tho in that situation, I'd far & away give preference to hoof function/health over longevity anyway.
Last edited by loosie; 03-05-2016 at 06:20 AM.