In my opinion, the internal recommendation can only go so far with the simple fact that a large majority of applicants have pilots submitting recommendations for them. The internal recommendation "gives you a look" but if everyone is just as qualified your look may take a while to equate to something. My understanding is that its putting you in a separate pile of applicants which is also very high.

One of my buddies had his application in for a couple years with several HR emails, but didn't get an interview. He attended a job fair and met face to face with the HR rep. He received an interview very quickly after the job fair. It makes me regret the fact that I missed it.