Pros
Crossmark's many business relationships allow you to work with a very diverse amount of companies, including (based on my experience) Shop Rite, Walgreens, Rite Aid, A&P and subsidiaries, Kings, CVS, and many more, which if you provide enough service to these stores, you learn a lot about their operations and employees, and thus can open up advancement opportunities through them.
Cons
On site supervision from your CROSSMARK supervisor is non-existant except for perhaps a week or two post hiring. While your supervisor can help you and give leniency when dealing with absences or inability to perform work, it's based on what you have reported over time, not actual onsite supervision of your skills. Thus, advancement within CROSSMARK is minimal.