I stayed at Poly a week ago and we went to Trader Sam's a couple of times. The experience was hit and miss. It is hard to get a seat. The host will give you a pager should a table become available, but seating is first come first serve, so there is no guarantee. This makes absolutely no sense, but it is the truth, the pagers are somewhat useless. Your best bet is to send someone into the walk-up bar area and hawk a table as soon as it comes available. We had parties of 5 or more each time so this was necessary, if its only 2 people its much easier.
As for the experience, it depends on the servers. We had a great experience with Cory and Nick, however the servers rotate every night. To make it worse, they don't know if they will be inside or outside (at Trader Sam's Terrace) until they come on shift. Outside is not nearly as fun as inside. One night the servers seemed like wet blankets, but maybe it was just because Cory and Nick were so much fun.
The drinks are good, but sweet. If you like fruity cocktails, you will like Trader Sam's. Almost every drink has some kind of shtick (a saying or action the servers will do), which you will experience as your drink and other peoples drinks are served. Some drinks are more involved like the Nautilus and Uh-Oa!. I really liked the Misquito Mojito and Dark and Stormy since I am not into fruity drinks. The Spikey Pineapple is made with Dole Whip, since Poly is the only place outside of Adventureland you can get it. They also have a full bar so you can order any drink you want.
Like I said, hit and miss, but if your over Poly way its worth a trip. Also, weekends are better than weeknights. More people better atmosphere.
Hope this helps.