If you're willing to put up with the many quirks of the owner, you will have a delicious meal. It may take a while though.
Between the menu full of ingredients she didn't bother to purchase (beef and pork the day I was there) and her inability to handle a group of 8 without constant complaining ("large groups really should order ahead"), the dining experience here was a comedy of errors. We sat down and ordered prior to 2 groups of 2 people each. They all received their food before us. Our group's orders came out sporadically between 45 and 60 minutes after we ordered. Some items never made it. When we were charged for the no-show items and pointed out her error, she told us we should have come back to the kitchen and told her. !
The food was good, but Thai Touch on Washington Road in Mt Lebanon is every bit as delicious and they offer a full menu every day with excellent, efficient service. Go there.
P.S. The owner of Thai Suan Thip would not allow us to BYOB.