I have been to the Chelsea for multiple country concerts and honestly I feel it is such a great venue to visit! It is very small, only housing around 2500 people max on the floor and balcony.
The stage is at the front of the venue and the standing room area isn't large at all. The seated main are great if you can get those but they do sell out quickly. The balcony seats are even good, they give a different view from above looking down at the stage. The standing room floor is intimate and small enough to see the stage and performers even from the very back which is amazing when you are singing your heart out to a performer you love!
There are multiple bars set up for convenience and springs underground to help the floor bounce when the crowd is jumping up and down!