I made reservations for LOS long before arriving in Vegas for my first ever visit after hearing so much about it on the chowhound message board.
I became sketched out when both the employees at the Palazzo and my cabbie had never heard of the place and I had to give directions. The next thing I know, we're off the strip and getting dropped off at what appeared to be a run-down strip mall. Queue the dirty look from the girlfriend.
I was somewhat relieved once inside LOS, although wasn't sure what to expect given that there wasn't anything too special about what was inside.
Anyway, all that really matters is that the food is amazing. I eat a lot of Thai food and generally find it hard for a restaurant to do it really poorly or really well, and LOS managed to impress me. Her specialty is Northern Thai dishes, so be sure to try something you may not be accustomed to if you're used to Bangkok Thai food, like I am. The best part of all is that the food is incredibly reasonably priced.
Also the first thai restaurant I've been to with a wine list (though small)!
Be sure to check out the pictures on the wall of all the celebrities that have been patrons (including many famous chefs)!
As mentioned in the other reviews, reservations are key. This place is often booked up days in advance.
I give it 5 stars for terrific value, superb Thai cuisine, and for being a refreshing break from the over-the-top glitz (and price) of the strip.