I've used both the UK e-Gates (LHR T3) and Irish ePassport gates (DUB T1) recently. Of the two, I preferred the (SITA?) gates at DUB; the passport read on the first try (LHR required me to try two or three times) and the "two stage pipeline" design seemed more efficient to me.

(For those who haven't used these: there are two sets of gate doors. Before reaching the first one, you scan your passport; once those open, you enter and in the area between the two sets is the facial recognition camera. This allows one passenger to be face-processed while the following passenger is scanning their passport; once the first passenger leaves, the second doors close and the first doors open to allow the next passenger to be face-processed.)