As the biggest city in Tohoku and a major business centre, Sendai has an abundance of hotels for visitors to choose from, with plenty of good deals to be had. Checking my options for a summer visit one time, I found a great one: four nights, very reasonably priced, at a cosy hotel with great service, in the very heart of the city.
Disclosure: I'm a big fan of the Dormy Inn chain, and staying here has only made me more of one. My room was a little plainer than others in the chain, but a little more spacious, with a handful of hangers for my clothes, and the usual little fridge, TV and desk, complete with LAN sockets, though there's also free Wi-Fi throughout the hotel.
One of the main selling points of the chain for me is the sauna and onsen baths at each hotel, as I like to start and finish each day with a steam and a soak. The sauna here is pretty small - more than four men will be getting pretty cramped - but very hot, and I actually brought myself to dip in the cold bath.
One point to note is that at this branch, there's a public bathroom only for men. However, guests here are also able to use the bathroom at the nearby Dormy Inn Annex, which has facilities for both men and women, and an outdoor bath that's nice to experience in cold weather.
Guests here also get showered with little treats. There are free probiotic drinks in the morning, free ice cream from afternoon to evening, and if you come back peckish after 9:30 a cook will serve you up a bowl of ramen for gratis. Also, and uniquely to this branch, there was free evening alcohol! At the time of writing, each guest is allowed two cans from ice-buckets of beer and highballs in the lobby.