I'll give you my feelings on them, and why I chose to add them to the store.
1: There aren't a lot of options for shorter-bodied buttons.
2: If someone chose to, it wouldn't take much to mod them for lighting.
3: They are capable of having legends added to them.
4: The flat-top isn't bad. While they are not concave, they also are not convex like many similar buttons. Sort of an in-between.
5: They are very smooth actuating, especially with our custom switches. And due to the position of the switch actuator leg, they have a nice, tight switch response.
If there are any real negatives, other than those looking for concave buttons, I would say it is the bezel color. Not sure why, but white doesn't seem to be very popular. This tends to limit their use to those with more unique designs.