In my estimation, the small reflector type lights like the PD35, the thrunite Neutron 2C, the Niteye MSC20, are great out to 100-125 feet. Yes, they'll add light out to 150-175, but not enough for me.
If you want to get out to 300 feet, then they are too small. A P60 dropin should work.
I don't have any Surefires, so I can't compare them to Solarforce, but I do have a Solarforce L2M, and a L2N. They feel sturdy, and the threads are cleanly machined. I also have two of those cheap ebay xxxxxfire knockoffs that are the epitome of cheap- NO-Quality-control what-so-ever! Although they take P60 drop-ins, the first had a wire so poorly soldered to the emitter, that it fell off within a week. The second was a replacement by the seller. The treads on the body for the tail-cap were so poorly done, that they stripped while putting the cap on. I took the drop in from the replacement and put it into the body of the first and had a working light. I soldered the emitter of the first, and bought the Solarforce L2N, and now have two working lights.
It seems to me, and others have stated that getting one of those cheapo's are a crap shoot. Many feel, not worth it.
I don't know, but let's say that the manufacturer is going to do a 1,000,000 piece run for two different companies.
The quality company may want them to change the cutting tools and adjust the equipment every 50,000 pieces.
The cheapo company may just want a million pieces for as little money as possible. The cutting tools and machinery are dull and sloppy at the end of a million piece run. So if you get one of the first machined lights it may be ok, but if you get the one millionth light it'll be total crap.
Within the last year, I bought a $150 three emitter highly recommended search light and one of the three emitters was bad. Another $100 light with pretty crappy tail cap threads (they were functional, but there were small pieces of metal missing, little chips in the threads), and a $120 light with a bad switch. I bought a home depot - Defiant super thrower for $25, that when the body was threaded for the head or tail-cap, the coil of metal that was cut away was inside the head in a jumbled mess. None of these lights were made in the USA.
I am surprised that we don't see more reviews of the Solarforce lights. I only have two of them, but I don't have any complaints with them.