UK has had near-real-time transfers for a while, it's called "Faster Payments" and there's no fees for end-users. It's also a "push" system (and not a "pull" system like ACH) which has serious advantages -- you can send money to anyone given their sort code and account number, and those numbers do not need to be kept private. With ACH if you have someone's routing number and account number you can pull money from their account without them needing to authorise it.
Same-day ACH is just ACH with more batches, it's the same old shit cooked a little faster.