1) They do not train you at all. This company is very sink or swim - there's no formal training. In the four years I was here - any formal training department was systematically eliminated one person at a time. You better hope that you get good training from whoever was leaving's two weeks and the figure the rest of the stuff out.
2) The customer will hate you. Period. They will dislike you, dislike the company and dislike the product.
3) You will never, I mean never, get a salary bump that's more than 10%. If you start, work here for a couple years, quit and come back - you have a higher chance of being paid market than staying here long term. I watched employees who have worked here 5, 10, 15 years get outpaced salary wise by new hires simply because the company will never bring you up to market. You better hope to start off at a really good salary and never deviate from that.
4) Someone somewhere in the pipeline will jealously hoard onto information that will prevent you from moving up or doing your job effectively. This company fosters an environment of secrecy due to rolling layoffs. It's layoff season atleast twice a year.
5) You will grow in the company due to the work that is being done but very rarely will you get the title/compensation to match it.