I first tried to go to Landia a year ago, and after schlepping around Vienna for quite a while trying to find it's slightly obscure location, I arrived only to be told that they were shutting early due to a lack of custom. However, on my next trip to Vienna, I managed to go again after much effort (it really is a bit tough to find), and found it in a much healthier situation.
The staff were very friendly, and patient with our poor attempts to pronounce things in German and our need to have certain bits of the menu explained to us. The food itself was...well, I feel that I can't be too harsh on it, as I am coming to the realisation that I'm simply not a big fan of central European cuisine. A lot of the food is vegetarian and vegan equivalents of traditional dishes from this part of the world, like goulash and schnitzel. In that sense, they were perfectly successful, I just find much of the local food a bit bland it seems. To reiterate, the problem is with me, not them, I think Landia did a good job of what it was trying to do.
Excepting my taste issues, the place was very nice, a cosy atmosphere, friendly staff, good beer, and a reasonable price. If you're up for potatoes, breadcrumbs, cheese and 'ham', this seems like a fine choice.