Appearance wise the CM Storm Sentinel Advance II does alright. Like the very first Sentinel mouse from CM Storm this one features a customizable light system which is a real treat to modders.
The thumb buttons a located perfectly for people with average sized hands. People with large hands will probably find them to be a bit too far to the back of the mouse.
The mouse feet used are made from Teflon. The positioning of the mouse feet is a bit odd and it leads to the mouse not sitting quite as steady on the mat as e.g. Microsoft IntelliMouse Explorer 1.1 (IME 1.1), Zowie AM or a Mionix Naos 5000 for that matter. The center of pressure when pushing the primary buttons is for example further forward than the most forward pads which can be felt more or less depending on how you grip the mouse and how hard you press.
Behind the small bezel you find the weight system. It effectively allows you to tweak the weight of the mouse. The implementation is alright, but with each added weight the weight distribution changes a lot. The Mionix approach with the weights situated in the center of the mouse around the sensor is much better in this respect.
Size wise the Sentinel Advance II dwarfs both the recently reviewed Zowie AM gaming mouse and the now ancient IntelliMouse Explorer 1.1.
The scroll area suffers from button congestion, while it does not look particularly clean all of the buttons are actually useable albeit the one located in front of the scroll wheel is less accessible than the other two. The buttons south of the scroll wheel allows you to adjust the DPI setting up and down with default key binding. Notice the bump on one of them allowing you to tell them apart by feel.
Side buttons are definitely a must have on any gaming mouse and the Sentinel Advance II has two which are located pretty darn close to optimal. The feel of the side buttons is great they are firm and have a rubberized coating on them. The travel length is short and the actuation force is semi high which is nice!
Furthermore the TX button can be used to expand the functionality of all the other keys by assigning functions that are enabled by two simultaneous key presses.
On the right side of the mouse there is just a hint of a bulge there to add some support for your pinky finger.
The top side of the Sentinel Advance II is very well laid out. At the center you have the OLED screen with an additional set of indicator LEDs just south of it.