I have been to Marnee Thai a couple of times. It isn't what I would consider the 'best' Thai food I have ever had, though I am not sure if I have experienced that yet.. though Lotus of Siam is pretty bad ass in my book.
What i do like about Marnee thai is that they are open late until 2 am. It's not the latest open place in China Town, but it's always a good option when a place is open that late.
I have never shown up for any special event, only for the curry, pad thai and stuffed wings (of which i have had much better) .. but the little older man that sits at the the karaoke stage and sings Lionel Richie and Commodore's covers .. in Thai... is a nice touch ; ]
he bill is always about $45-$60 for two of us with beers, so it's not over the top pricey .. in fact i think the Chicken Pad Thai is $8.99.
Id give it a try if you're looking for late night, low-priced, still pretty quality thai food.