I always think of this line when asked for a reference. Today Crikey carried a whole bunch of similarly ambiguous one liners for references from LIAR The Lexicon of Intentionally Ambiguous Recommendations.
They’re over the fold.

• I cannot recommend this person too highly.
• I recommend this candidate with no qualification whatsoever.
• He has made immeasurable contributions to our firm.
• In all the discussions she and I have had over the years, her salary never came up.
• I simply can’t say enough good things about him.
• I am sure that whatever task she undertakes — no matter how small — she will be fired with enthusiasm.
• I am pleased to say that this candidate is a former colleague of mine.
• She is always trying.
• He is a difficult man to replace.
• She is one of the most discriminating people you’ll ever meet.
• He will take full advantage of his staff.
• She takes a lot of enjoyment out of her work.
• His input was always critical.
• I found myself frequently raving about her work.
• I would place this student in a class by himself.
• She is now ready to strike out in a career.
• He is resigning a position that he has held with our firm for years. I truly wish there were more people like him.
• We were teetering on the threshold of bankruptcy last year, but her efforts pulled us through.
• For the services he has rendered to our firm over the years, we find ourselves deeply indebted.
• She works without direction.
• He works effortlessly.
• To get the job done, we need ten employees like her.
• Attacking a difficult challenge, she doesn’t think twice.
• You should seriously consider initiating an offer since she probably won’t apply herself.
• When he worked for us, he never did anything halfway.
• We were forever asking her for new ideas.
• You can’t offer this man too high a salary.
• How did she manage those who worked for her? Quite fairly.
• There is nothing you can teach a man like this.
• She was never way from the job too long.
• He is only 30, but he has the mental faculties of a man three times his age.
• I would place her research on the cutting edge.
• His potential clients always wind up giving him the business.