This was a mixed bag of a stay – Gareth's place is in the really trendy, vibrant docks area of Dublin, with good transport links both to the city centre and to the airport and ferry terminals, plus has lots of local amenities close by. He's a friendly and attentive host (he lives in the flat), with great communication, and went out of his way to be helpful during my stay; he'd stop for a chat if we ran into each other, but never intruded in any way. The WiFi connection was strong, fast, and reliable.
However, the room itself was slightly disappointing. First, it wasn't the room shown in the listing (I'm guessing it was the other one available in the flat), but a smaller one with a less attractive view. (While this didn't bother me, it might disappoint others.) There also wasn't access to a TV (which I think must have been in Gareth's private living room).
Second, the room wasn't in good condition: there was what looks like a long-standing problem with the balcony door, which meant that it couldn't be fully opened (and so there wasn't any access to the balcony, despite this being promised in the listing) but could only be tilted back to allow ventilation. However, the balcony door couldn't be closed properly, meaning that there was a constant draught (which was particularly noticeable during my stay because of high winds), which the room's electric radiator could only partially remedy. This also meant that there was considerable damage because of damp in the room (peeling paint, damp spots on walls), which could be an issue for a visitor with respiratory issues.
The bathroom and kitchen were fine – while there was plenty of crockery and cutlery available to use, the shared fridge is small (and doesn't have a freezer compartment) so don't count on buying lots of food all at once to go in there (although with two supermarkets and several restaurants/cafés close by you shouldn't need to).
Whether or not this room would suit you would depend heavily on how much time you planned to spend in the room: if you'll be out most of the day and just use it as a place to sleep (as I did), then it'll be great; but if you plan to spend substantial amounts of time in the room, then it might be less suitable.