I was a solo traveller with a hire car.
It says Sondika but you have to leave Sondika (under the bridge for another half K - if travelling from the east) to see the high-rise sign.
There is free parking - it's not obvious but you have to drive accross the brick area in front of the hotel to get to it.
I've read the other reviews and yes, the carpet in the landing is well worn. In fact the whole place could be classed as little weary and perhaps a lick of paint would make a difference if you are occupied about these things. I thought it all hung together reasonably well, Everything worked, from the shower to the in-room safe, and was clean.
Didn't eat there.
The in-house bar was closed on my night there but there is a bar/restaurant almost next door which I went to for a final beer (or two) - looked ok, but judgement was possibly a little fuzzy by this time.
It's a E15 taxi ride (each way) to Bilbao town centre for all the entertainment you could want. I went to the Guggenheim - E8. I suggest worth the money even if you're not normally interested in that sort or art.
If you are returning a hire car the next day - as I was - turn right out of the hotel, it's about 10mins drive (all signposted) and there's a petrol station on the way to fill up. Stay alert though, at one point you join a motorway for only about 200yds before turning off again ....lord knows where you'll end up if you drift past that....
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC