I love the Polynesian but couldn’t afford it this trip so we are at CBR. Trader Sams is new since the last time we were there (5 years ago). We would like to activate our military vouchers Saturday afternoon when we arrive in town but don’t plan on going into a park that day. Going to do this when we arrive so our tickets are ready and active for Sunday morning when we go to MK and we don’t have to deal with Guest Services at 8 am at rope drop.
We have a TREX reservation for Tuesday night at Disney Springs but wasn’t sure if going there on our first night in town would get us in the Disney mood or whether it might be more fun at Trader Sams. Thanks.
I would say go with what you would want. I have never been to Trader Sams, even though we stayed there in Feb. T-Rex is fun but loud. I have eaten there 3 times 
But you could also walk around DD while you were there and have some free time. What time are you arriving?
Do you have kids? I’m assuming so with a T-Rex reservation. Be aware that they aren’t allowed in Trader Sam’s after 8pm. We love TS but it is very small inside and is often a wait to get in. We haven’t tried their food but we do enjoy stopping in for a drink.
Trader Sam’s can be a lot of fun, but as @Outer1 said, no kids after 8:00 PM and possibly a wait to get in. The outside terrace is nothing very special, so if you can’t get into the actual bar, I would skip it. Food is basically bar apps. The ones that I tried were OK, but not spectacular; as a snack while enjoying the drinks (the “real” reason to go) they’re fine, but I wouldn’t make it my “dinner”.
DS has a LOT more options from signature dining (Boathouse, Morimoto’s) to regular TS (RR, Paradisio) to QS (EoS, WP) as well as some cool places to stop in for a drink and apps (Jock Lindsey’s). RR is one of my favorite restaurants in all of WDW. With no kids, T-Rex is NOT my idea of a nice dinner out; just TOO noisy and frenetic. I stopped in for a drink one time, and that was enough for me.
You could have “the best of both worlds” and stop by TS for a drink and to enjoy the atmosphere, and then go to DS for “dinner”…
I’ll echo what others have said about Trader Sam’s. I was really looking forward to trying it out, but when we arrived at around 4:05 all seats were taken and it was standing room only. And it’s hard to grasp just how small the inside space it from online pictures and blog posts. The place is TINY! We ended up bailing out and going elsewhere.
We prefer a non-park evening, whether that is at DS, our resort, at another resort… For us, using a park ticket for such a late-day entry feels wasteful. For others, it’s part of the excitement. I just know that we cannot withstand a full day of travel and a whole night in a park and expect to be in good shape the next morning. So we lay low and head to bed on the earlier side so we an go at it hard the next day!