Sat here for the Ravens game that went into overtime back in 2012. Outstanding atmosphere that day, tons of Ravens fans were in attendance since they play only a few minutes down the road. I've sat in the end zone sections for almost every Redskins game I've attended. The tickets are just too expensive the closer you sit to midfield and I enjoy sitting down next to the field to soak it all in.
136 definitely gives you a better view of the sideline than any end zone seat I have ever had. It kind of has the best of both worlds. The only downside is only having one jumbo board in your plain view with the other to your back.
This stadium is completely enclosed so it's very loud when at capacity.
As a visiting fan, one thing I think you'll enjoy at Fedex Field is knowing that the Redskins fans aren't the least bit hostile. You show up in the tailgate lots with a Giants or Eagles jersey on and people will offer you a beer and Italian sausage. They're that friendly despite a little friendly banter.