One thing about recommendations: make sure your app is perfect before you ask a current DL pilot send in the letter.
I know it's been said here before, but you definitely do not want to put yourself into a year-long holding pattern because of spelling/grammar/consistency/content issues.
That's for the applicants.
For those doing the recommending: If you're willing to take the time to send in the rec and really want to help someone, make sure to take the time to review their app, and insist they have at least a couple other folks look it over for the nit-pick type details. My bet is that every successful recommend-er insisted on seeing the app before sending in the recommendation.