I've eaten there and loved it. The food is incredible, with careful attention to detail and intense, well-balanced flavours. The dishes we tried were just right (to my taste).
Prices are obviously incredibly high for Bangkok and this can't be compared with street food (you can be eating fantastic Thai food on many street corners for 30-60 baht but there are a lot of dishes that you just don't find very often). Also I feel that there was a definite lack in Bangkok of restaurants serving fantastic Thai food in a more upscale environment - you generally need to choose between plastic stools and delicious food, or fancy decor and bland food (with a limited menu of the usual suspects).
David Thompson may come across as arrogant in what he says (the article was actually deliberately slanted that way - an opinion piece and a bit tabloid-like too) but he's not saying anything that a lot of people (I mean Thais) haven't been saying and feeling for ages about a lot of the Thai food available at restaurants and on the streets these days. One lady actually gave me some limes when I asked if there was a som tam vendor nearby ("because they're not going to use real lime juice"), while a couple of good friends often bring round food "mum made, because you won't find it that way anymore". It's just that DT is not Thai, so naturally it comes across as insulting.
His restaurant (and Bo.Lan, too) may be out of reach for the vast majority of Thais, but many yearn for food that is "the old way", and will seek out places that still do things "from scratch". Read DT's Thai Food and you will find a man who is profoundly in love with Thai cuisine and is passionate about preparing it impeccably.
Personally not blown away by the decor, but was too busy eating to mind! The menu at Nahm had a lot of my favourite dishes (gaeng som, gaeng dtai bla, various types of nam prik and yam). They were very spicy but not excessively so if you normally eat Thai food as opposed to Thai food lite. I didn't find them overspiced and definitely not either too salty or too sweet (by comparison, the food at Nahm London was overwhelmingly sweet, and not spicy enough). It was delicious and memorable and if money grew on trees I'd go back tomorrow (I'll ask for tap water next time!!).
Having said all that, I don't think I would take many of my non-Thai friends or family, because it would probably fall under the heading of extreme Thai dining in their eyes! The menu doesn't offer a lot of "classic" Thai dishes as per menus in Thai restaurants abroad (green curry, red curry, cashew nut chicken ;) It is spicy, pungent, bitter, sour...There are a lot of acquired tastes in there.
The night we ate there, there were a lot of Thais dining there and they were impressed. When so many upscale Bangkok restaurants are about creating the right look, or following the latest fashion, Nahm is a welcome addition. And maybe the final comment in the NYT article sums it up.
That's it. One of my favourite places, and a good one for taking visitors, too.
Almost didn't notice how old this post is! But still....
There is a small restaurant off Silom (soi 3 I think) serving only kao soy and kanom jeen nam ngiaw (and rice cooked in pork blood). It is called guaytiaw sipsongpanna and it's on the right as you walk down from Silom. Might not have an English language sign, I can't remember - look for the cooks out front. I usually have the kanom jeen but I've tried the kao soy and it's good.
If you're up for a challenge, I'd try the last restaurant on the CNNgo list, Maan Meuang. We've been going for a while now since the author of this article wrote it up on his blog. I haven't tried the kao soy but they have a long menu of northern food which is exceptional. One of the comments to the article says the place has moved but the commenter couldn't find it. On my second to last trip, they told me they were moving and gave me a map in Thai, but the best bet is to call their mobile no. and ask for info. Or get a Thai person to do it for you. It really is worth the effort; their dtam kanun (young jackfruit salad) is fantastic.
Another good northern place (I love northern food, can you tell) is Gedhawa on soi 35. I think I've tasted their kao soy but again it was kind of eclipsed by some of the other dishes on offer (nam prik num and various other incredible nam prik, gaeng kae...) The family that run it are really sweet, too. Compared to Maan Meuang, the food is much more artistic, but Maan Meuang probably has the edge in terms of flavour. (Also, Gedhawa does food from other regions but we avoid that now after a few - relative - disappointments)