Hank, he wasn't asking about the Royal Dutch and, while you might personally find the Royal Dutch preferable to the Nuevo Johnson, it is not even remotely near to the same low price range, so how can you really fairly compare the two places. The RD website does not give rates and that other thread only says that the RD is about $6 less than the Morazon, but that would put it at least in the $40 price range or more and at least 2.5-4X more expensive than the NJ. So, let's try not to hijack this thread. He was asking about the Nuevo Johnson (or perhaps other ultra-cheap hotels that are comparable).
Also, from what I've seen most of the most negative commentary about the NJ seems to come from guys who would never really even consider staying in hotels in that price range in the first place and so have never actually stayed at the NJ themselves and also probably have never really even checked it out. And even if those guys HAVE checked it out, since they'd be viewing it from the perspective of guys who would never even really consider staying at such a place, their perspective on it would be unfairly biased.
I've actually stayed there a number of times myself. But I don't always stay there. I've also stayed at more upper end places (over $100/nt) in both SJ and elsewhere in CR and actually stayed at hotel in CR that was even cheaper but not as nice as the NJ (and one that was not as cheap OR nice), if you can believe that. So I think I can be a bit more objective about it.
So, from my perspective, I think the fairest way to describe the NJ is that you get what you pay for, and probably more than most hotels IN ITS PRICE RANGE but not much more. Anyone that expects the Four Seasons, or even the Royal Dutch, for the $10/nt they charge is really being unfair and unrealistic (yeah, I know the website says $15 but they've always charged me only $10/nt during the week).
The pro's, and they may not sound like much compared to the midlevel and upper end places that most CRTers are more used to and where such things are more of a given, are that you get a reasonably clean room, with a reasonably secure lock (and good security at the building entrance level), a private bathroom with more or less hot water in the shower and a color TV. Believe it or not, many hotels in that price range don't even offer all of that. If you want a standup floor room fan at the NJ, you have to ask for one (they are effective but can be noisy themselves). And if you want to lock something up you either have to leave it with the front desk security or hidden and/or locked in your luggage in your room (with the staff and doorlocks there, I've actually always felt comfortable enough doing the latter). The con's are the aforementioned paper thin walls (personally I'm not a light sleeper and they have never bothered me), the TV gets only a few spanish language channels (and scrambled Playboy

) and then only fuzzily and that the place is a bit rundown (as CalDude has said). Its hardly a cheery place that you'd want to spend the rest of your days, but if all you're looking for is a reasonably clean, reasonably safe and very cheap place to park your bones at the end of the day after going out enjoying yourself elsewhere in SJ (or a tiring and busy day of apartment hunting) and then only for a few days, then it might just be your place.
As for room selection, I've never stayed on the side near any fish vendors or even really know what CalDude was talking about on that, so can't comment on that aspect. OTOH, I do think you'll find the inside rooms quieter, at least in terms of getting the noise from the street. Noise from rooms on the other side of the air-circulation well in the center of the hotel may be another story, still I think the inside rooms are probably your better bet. Also, while I never actually had a problem with room security at the NJ, the inside rooms on the 2nd floor (3rd from the street) have unlockable windows that MIGHT be accessible from other rooms across that circulation well and so have always made me a little nervous. So I'd try to get a room on one of the upper floors if you can both for reduced street noise and greater security.
Some other comments re: the hotels common areas and neighborhood. They have a pooltable room and the (nicaraguan) staff there is excellent. Here are some of my own tips: bring some coffee back for the guy at the front desk after grabbing some breakfast next door at the Central Market in the morning and tip your maid for extra towels at the beginning of your stay and they'll all look out for you and keep you more than well supplied throughout. As others have said, the neighborhood is not one you'd want to walk around in at night after the area businesses close, but it is safe enough during the day. Besides, unless you were staying at the Morazon or HDR, you'd probably want to take cabs to the BM and KL (or any place other than the SL) that you might want to go after dark anyway. How many guys advise walking more than a block or two anywhere in SJ after dark anyway, so that really seems to be a somewhat contrived "issue" to me. It is a bit farther walk to "Ground Zero" during the day than it is from the Barrio Amon/Otoya area hotels, but the walk along the Central Avenue Promenade is pleasant enough and it sort of makes up for that by being closer to other amenities like the Central Mercado, most of the intercity bus stations (including the one from the airport) and many tico MP's (as others have already stated).
BTW, I'm not sure why Nhhank says it is not the best place to taxi to. It is really no better or worse for that than any other place. And actually there are always a lot of taxi's passing by in that area, day or night. If stepping more than a few feet outside the front door of the hotel to flag a passing cab really bothers you that much, then just ask the security guard to do it for you. Oh yeah, and no need for Diacort since it is a HOTEL and not a restaurant.
Lastly, I've only stayed there when I've planned to leave SJ EARLY the next day by bus and have never taken chicas there myself. Some guys have said that they'd somehow feel embarassed or something taking a chica back to such a rundown place (I guess they'd rather impress them with how much they have to spend by taking them to a much more expensive hotel). IMHO, that attitude seems rather silly to me. Frankly, these chicas live in very humble surroundings themselves and probably couldn't care any less how fancy your hotel is or isn't (and when I'm screwing a chica, I'm not really admiring the artwork on the walls either). For the chicas, all I really care about is that it has a bed. And all they really do care about is the color of your money. If anything, seeing you're staying at a place like the NJ, will be more likely to help convince them that you really don't have Cien to pay.
I've never needed any reservations whenever I've stayed there (unlike the more "upscale" places). I suggest you just check it out when you get to CR. If it looks, woo, too scary for you when you finally see it for yourself, you can always just hop in a cab and go to a "safer" "classier" and more expensive place (or even walk with you bags around the corner to the RD or the Doral). Worse case scenario, those other hotels are all booked up and you wind up spending 1 night at the NJ until you find a more desirable vacant room somewhere else.
Thanks go out to JB for the links to info on the Royal Dutch for anyone that is more interested in that topic or who'd rather discuss it in a more appropriate thread. For those who are interested in the Nuevo Johnson, as was the poster who started this thread, you might also have tried the search feature which would have directed you to at least 8 other threads already dedicated to this hotel:
http://costaricaticas.com/forums/search.php?keywords=nuevo+johnson&terms=all&author=&sc=1&sf=titleonly&sk=t&sd=d&sr=topics&st=0&ch=300&t=0&submit=Search