I booked an ex-Dublin to NYC flight for later this month. I'm flying Club for less than you'd pay for WT+ from LHR, but getting to Dublin turned out to be a squeeze. You basically have to take a full day off work for a flight that departs 18:45 from LHR. I have things I can take care of in Dublin and will go the night before, but it's a tougher call.
LCY can be your friend if you work it right, but the times have to line up. In my case I could've taken City Jet at 13:45, landing 15:00, but any delay would've caused me to miss my BA flight from Dublin at 16:00.