I must confess I went to Nights of Kabul more out of morbid curiosity than any expectation of quality. The last time I went to an authentic Central Asian restaurant in my area it was, uh, a little bit too authentic - we were basically served perfectly-cooked meat with pickles and not much else in an environment which accurately reflected the country's history as a Stalinist republik. (That particular restaurant has since moved, and its interiors certainly look a lot nicer now - I'll try to check it out sometime, as the kebabs were magnificent.) So I rolled along to Nights of Kabul full of hilarious speculation on the decor and possible entertainment (that would be Buzkashi, not wife-carrying, although the restaurant that offers that as weekend entertainment will be guaranteed all the publicity you can eat).
The decor, I have to admit, is not amazing, and we didn't go on a night when they had live music so I can't comment on it. The restaurant is licenced, but if you do drink I would advise you to stick with nice safe beer, which is supposed to go with this sort of cuisine anyway. Afghan food is supposed to be similar to Indian, and you'll notice several familiar items such as tikka, korma and gulab jamun. However, you should probably not go in thinking "Oh, it'll just be like Indian" - my mum ordered a mixed tikka, thinking it would be like the mild tandoori style you get in most Indian restaurants, only to find it was like eating a mouthful of pepper. Conversely, I ordered the mixed Soltani and it was absolutely delicious. We also got a mixed entree which, despite the somewhat colourblind image on their website, both looked and tasted incredible. After we pushed our chairs out to accommodate our humourously-distended stomachs, dad insisted on having a Turkish coffee, which was served in an adorable little dainty teacup. I had a sip and was expecting it to be like chewing a Gauloise, but it wasn't - it was sugary and perfect. If you're the sort of person who doesn't normally eat dessert I highly recommend it.
If you're the sort of food nerd who goes to restaurants based on how exotic they are I can recommend Nights of Kabul, but if you're the total opposite and just want to be fed until you explode then I can still recommend Nights of Kabul.