I have been with the company I am with for 6 years now and have recently been recommended for a position at another company by a friend. I have been trying to get promoted at my current company for over year now. The comments I receive back from the hiring managers are "You have the skills and interview well but as long as someone else is applying already has the same title as the position we can't promote you." I definitely am a top performer and am doing many responsibilities of a higher level position.
I have been looking primarily within my company for a promotion but I am currently interviewing for an opportunity with another company that is a lateral move. The company is ranked third in it's industry as a "best place to work" by Glassdoor.com but when I look at the comments on that website from employees at the location where I will work they are not as positive. The company is known as providing top pay and benefits but I have heard some comments that they don't always promote from within either. My friend who recommended me felt the atmosphere was great at the site I am interviewing for but does not work for the company.
I don't want to take a lateral move (even at substantially higher pay) just to be told again that they won't promote from within. What process and resources should someone use when evaluating a company they are thinking about working for?