The best English translations of the Church Fathers are, generally, those published by the Catholic University of America Press under their ‘The Fathers of the Church’ series.
They are the best for a variety of reasons:
(1) They are authored by the leading authorities on individual Church Fathers;
(2) They use the most up-to-date, critical texts for their translations;
(3) They often translate Fathers whose works have never been translated into English, including St Barsanuphius of Gaza and St Andrew of Caesarea;
(4) They’re scholarly commentaries, in that they include a thoughtful introduction discussing all aspects of the work (historical, theological, social, etc.) and a brief commentary.
(5) They’re not technical commentaries with obscure line-by-line analyses, so they can still be read by laypeople.
The big negative about the CUoA Press series is that their publications are expensive: both volumes of Eusebius’ Church History are $200 (in AUD).
Apart from that, Pengiun and Oxford often publish select, notably works by the Church Fathers. I note that Penguin has a widely available translation of Eusebius.