My wife and I stayed at AC Hotel Huelva by Marriott for one night on the way into Andalucia from the Algarve. Huelva itself is an industrial town, though the industry is on the coast and the hotel is fortunately on the north side. It's near a main road junction (thus easy to find, and also well insulated from any noise) although be prepared for the one-way street past the hotel. On-street parking was free and easy, and the hotel also had its own underground parking. Our room was very comfortable; it looked out towards an apartment block, but the blackout curtains worked well. Breakfast, in a first-floor room overlooking the local boating pond and parkland, was fine. The hotel does not do lunches or dinners, but the receptionist steered us towards a local restaurant that was an easy five minutes walk away and was excellent: very busy but clearly loved by the locals too.
The hotel staff were very helpful at check-in and check-out. By mistake I left my camera in the room when checking out. We phoned later that day; they phoned back after 30 minutes to say it had not (yet) been found, but phoned again quite a bit later to say it had been found; we were able to collect it on the way past a few days later. All in all, it's a very good place to break a long journey, or if you wanted to visit the Donana National Park further along the coast road.