I love typing on contoured SA. It's my favourite profile. It doesn't have steps between the keys, so you don't have to raise your fingers when switching rows, the curves feel natural and the spherical tops "suck" your fingers into the centres of the caps. I find contoured SA the least fatiguing of all contoured profiles and my typing really flows best on them. One caveat, however, is that you should be using plate mounted, stickered switches to truly appreciate them as this prevents the innate wobbliness of MX switch stems to be exaggerated too much by the height of the caps. Also, the best experience is on a flattish angled board, a really steep positive angled board can feel a bit weird, due to the lack of negative angle on the keytops.
Second favourite is Cherry profile, preferably with thick, heavy caps like GMK, BSP or Gateron. Material doesn't matter to me as much as the profile, quality and weight of the caps (although POM is still my favourite). This works well on more positive angled boards, but the steps require raising the fingers more when switching rows and this creates a little more fatigue for me when typing.
I have only tried Poker II PBT thick OEM caps and I think they're acceptable. Almost as good as Cherry profile, but they feel a little less "natural" to type on, somehow. Hard to describe it, but my typing just doesn't flow quite as well on them as it does on Cherry, and it's not about lack of familiarity, since I've used OEM boards a lot before discovering Cherry and SA. It could just be that they have a bit more of a step between the bottom rows and the bottom row angle is steeper than Cherry.
Thin OEM caps are just not worth using, IMHO. They don't have enough heft to feel like "quality" and they don't dampen higher frequency sounds, so they sound terrible on bottom out and release.
This also applies to thin Cherry profile caps for me. I have some thin lasered PBT Cherry caps and I don't like them as much as the Poker II thick OEM caps.
