Which would you recommend; diode, vpl or Alexandrite for hair reduction?

As opposed to attempting to figure this out yourself, I strongly recommend going to a physician who has expertise in laser-assisted hair removal.  Any center which is truly dedicated to hair removal will have more than 1 type of device present.  I would find such a center and followed the advice they offer.  You may wish to get more than one opinion but I would limit your options to centers that have physicians who have a special interest in hair removal.

There are many choices for hair reduction available, so which is best can be quite confusing.  I would suggest consultation with a plastic surgeon or dermatologist that has a lot of experience with hair reduction lasers.  The best choice for you is based on your skin type.  When you are out in the sun, do you burn always, never or sometimes?  Do you ever blister?  How well do you tan?  What's your ethnicity?  These are a few of the questions you will be asked to help your doctor determine your skin type.  In general, I recommend the following lasers for hair reduction in the following skin types:Skin Types 1-2: alexandrite or BBLSkin Types 3-4: Nd:YAG or BBLSkin Types 5-6: Nd:YAGThe most important thing (probably more important than the particular laser chosen) is a commitment to a regular schedule of your series of 4-7 treatments.  You have to be very compliant with timing of treatments to get a good result.  Your doctor will explain this during consultation.  Commit to at least 5 treatments and I think you'll see good result.  Good luck and I hope this was helpful.