We stayed in the Ramada Encore in Letterkenny for one night at the begining of May. The hotel is clean, modern and the staff are friendly and helpful and we booked through Skoosh so the price was good too.
The only drawback is that because Letterkenny is a real party town - especially for Hen and Stag parties, the hotel was quite noisey. We went to bed around 2am and were woken up at 3am with noisey neighbours and people in the corridor. We were then woken up early (for a Sunday) at 9am by the people in the room next door.
The Ramada would be perfect for a mid-week break but if you are planning to stay over a weekend, be prepared for a noisey clientelle. Although, in my experience, this is a problem that all mid-range priced hotels in Letterkenny suffer from.