Got to say, from the profile images on SP's site I much prefer SA to SS profile. So let's try to stick to the topic in hand, shall we?
The topic of the thread is: “Is it hard to touch type on SA profile?”
Though it seems like the OP is mostly concerned with homing bumps, I decided to answer the thread title question more generally.
My answer is: I find touch typing on SA (assuming the keyswitches have straight – not angled – stems) to less comfortable than touch typing on sculptured profiles like DCS or Cherry or SS or curved-plate-uniform-profile boards like an IBM Model M/F. I find typing on SA to be relatively similar to touch typing on any non-sculptured profile, e.g. DSA or a laptop chiclet keyboard, though there’s a little bit of sculpturing to SA relative to those, and the number row should be slightly easier to reach. Someone who really likes typing on a flat profile like DSA or a laptop keyboard will probably like SA too. SA looks really pretty, and makes a nice sound, and feels very solid. Spherical tops are great fun.
Then someone else asked “what is SS”, so there was a response to that. I don’t think it’s particularly far off topic, since SA and SS are in some respects similar (spherical tops, high profile); seems pretty reasonable to compare one against the other.
Based on your “I much prefer SA to SS profile”, I recommend you try to find a beam spring board, or an old Honeywell hall effect board, so you can try something similar to SS in person (more specifically, they’re very similar to SA but the switches have angled stems). It really is very nice in practice.
But hey, use whatever floats your boat.
