I use a Raytech lamp myself, unfortunately, I cannot compare it to other brands on the market since this is the only one I have owned.  I purchased this one because it has the option of being portable as well as an AC plug in adapter.  I've used it in the field several times and It can light up specimens up to 10 ft away.  Obviously, the closer the better, but that will be true no matter how powerful your lamp is.  This lamp gives you the option of having two bulbs -- one short wave and one long wave, in order to cover the full ultraviolet spectrum.  Although there are minerals that fluoresce only under long wave and not under short those are very few.  I elected to get two short wave bulbs in my Ratech so that I would have a more powerful shortwave projection.  Not only do more minerals fluoresce under shortwave, but most minerals that fluoresce glow even brighter under shortwave as opposed to long wave.

http://www.usgeologicalsupply.com/raytech-raytector-5-2-portable-longwave-shortw...