I stayed at the Eurostars Oporto for five nights in July 2014. It's a business class hotel, not close to downtown, but (I gather) with good access for those with cars. I chose it because I have mobility issues, and use the metro and buses a lot, so I like to be very close to a metro stop, and the Eurostars Oporto is certainly close to a metro stop.
From the train station you need to transfer at Trindade on the the D line, but that's no problem. The Porto metro is a thing of beauty. Modern stations, with lifts and escalators, clear signage, and very modern trains. The hotel is in the middle of nowhere, between a hospital and a large number of apartment buildings, but the trip downtown only takes a few minutes on the metro.
Overall, I can recommend it with some reservations. The room was excellent, as was the bathroom. The front desk people were polite and friendly. The room had an electronic safe, good (but not especially large) TV, and a terrace (more on that later). There are two modern lifts (although one stopped working while we were there and they didn't seem in a rush to fix it). It also has a fridge and you can get supplies at the I.P.O. metro stop, which you can actually walk to, it's so close. The free wi-fi worked great.
I didn't eat there (breakfast seemed very expensive) but there are a large number of cafes across the street that are excellent, and very inexpensive. In fact we made it a point not to eat supper downtown and to have late supper near the hotel after we returned from a day of sightseeing.
I would stay there again, because it met my needs: very close to a metro stop, good eateries very close, good value for money, and excellent room and bathroom.
Now the reservations:
First, it's supposed to be an aparthotel. There is a fridge (which doubles as a minibar), microwave and stove in the kitchenette (this is the double room, not the apartment). Unless you pay extra the cooking pots and pans and crockery are locked away, making self catering much more difficult. I really only ever use the fridge in hotel rooms (this fridge had a freezer compartment so you could make ice cubes), but if you want to self cater, be aware.
Second, the rooms have balconies (or terraces), that have no furniture on them! No chairs, no tables, nothing! In the evening, when the sun is off the front of the hotel, it would be nice to sit out, and have a glass of wine in the cool of the evening without having to drag chairs from the room on to the terrace!
Third, and this is a minor inconvenience, Porto has a zone metro system. The base metro ticket is Z2, which lets you cross from one zone to an adjacent zone. The center of Porto is zone C1, across the river is adjacent zone S8 and the ever so nice Foz district is adjacent zone C2. If you are downtown in C1, the base Z2 ticket will let you travel pretty anywhere you want to go. The hotel is in zone C6, so a Z2 ticket will take you downtown but if you want to go from the hotel across the river or to Foz in one trip, you need a Z3 ticket. A little inconvenient, but I got the hang of it. If you buy a 24 hour metro ticket you kind of need to decide how many zones you will cross in any one trip during those 24 hours. In Lisbon on the other hand, a 24 hour ticket gets you everywhere the metro, buses, and trams go, without worrying about zones. The zone issue aside, Porto has about the best, most modern, public buses and metro trains I have ever seen.
If you want to save money, but like the idea of being in that general area and very close to the metro station you might want to consider the Ibis at the I.P.O. metro station (which I noticed when I was shopping, but I've never stayed there). It is super convenient and a lot cheaper, but it's an Ibis. If you've stayed at one you know what I mean. If I were to return to Porto I'd stay at the Eurostars again but I really wish they'd put furniture on the terrace.