This is one of those toss ups: do you want really cheap, big portions, or do you want excellent food? With Evergreen Thai, you can only have the first option.
The food is ok. Nothing wrong with it, but it is incomparable with some of the top-notch Thai places in the city (and some pretty close to it, too). That being said, you cannot beat their lunch deal for $12.50 where you get spring rolls, salad, soup and your main dish. Absurdly cheap. But again, it's not like you're eating at SukhoThai or PAI, so you get what you pay for.
The service is great - they are friendly and quick to serve. If you wanna grab a quick lunch, or do a takeout, that is cheap, low-fuss and with large portions, this is your place.
I personally quite enjoyed their Pad Thai and their dumplings, but had no patience for the red curry... too watery and just not that flavourful. Again, you get what you pay for...