A real gem. Tucked away in a slightly run-down part of town (but seemed very quiet). Next to a railway station but no trains to speak of. Had obviously been a fairly majestic "Station Hotel" about 80 years ago, and maybe gradually became less-used over the years, but although the bedrooms have been modernised, the dining room and bar are still a step back into an Art-Deco world of the past. The dining room was a joy to be in, and the food/service was excellent - one of the best dining experiences we've had in France or elsewhere.
The upstairs corridors reminded me a bit of the "arty" hotels you'd get in Amsterdam (gaudy!), but the bedrooms/bathrooms are nicely refurbished. Soundproofing between rooms could still do with improvement but not a real problem.
We went half-board and it seemed very good value - about £85 for the two of us - the meal and breakfast was almost worth that!
The town of Eu isn't too bad - quite a few shops and some bars, but probably not worth making a special trip to. Le Treport is the "seaside" part of EU and is a bit tacky (rather chavvy Paris holidaymakers in early July when we were there) but has a lot of good seafood restaurants.
The Maine Hotel in Eu would be a good place to stop for a night before a departure from Calais/Dieppe/Boulogne. Or visit it just to eat.