Pros
The employee discount is pretty nice, you can make connections by working in a place frequented by musicians and various industry people, and it might be a way for young musicians to supplement their meager incomes from music. The veteran sales staff are good and knowledgeable people.
Cons
The environment is internally competitive, potentially making the staff into sharks. Unless you work in a high-traffic store, the commission system (which is going to be replaced soon) is pretty unfair - you get 10% of profit and 1% of sale, and if that amount is enough to exceed your basic monthly wages (which are barely above the minimum wage), your wages for the month are then deducted from that 10% of profit; sort of like you're paying them back out of your wages for the chance to truly get your commision, which ends up being a small bonus. Aside from this, the commission introduces petty politics. Furthermore, in my store, I found too much of the management to be bullying narcissistic personalities. The store manager was notorious among some of the staff for being an intense and crass man who mainly cares about the numbers - a man who takes out the financial pressures that are on him from above, on those below him. To be frank, I felt like psych-ops games were being played on me and workplace bullying was taking place for my first 6 months or so.