The apartment is really well located to visit Barcelona, and if you are attending an event at the Fira its just around the corner.
The apartment would be fine for a couple, but not more, unless its small kids.
The furniture and fittings are fine, but the layout is a little strange. I think toilet and shower are on what used to be a rear balcony, now enclosed. so the toilet is directly beside the kitchen and there is no real door between them, and the bedroom window opens onto the passage between shower and toilet. Like I said its fine for a solo or couple.
The wifi is fast when it works reliably, which is usually the evening.
Expect some noise from dogs in next door apartment, and upstairs percussionist. But I guess its to be expected in close apartment living