Do you plan to use the light as an EDC light and carry it routinely or just as general use?
As you may know, Pentagonlights are larger and heavier than their market counterparts. They are also more well made than most, anodizing is very good, threads are smooth and brightness is consistent from lamp to lamp. The main attraction to Pentagonlight is their shock-proof lights for a fiar price. Prior to the companies existence one would have to spend a minimum of 130$ to acquire a light (Surefire M2) with the same amount of protection found in the 60$ Pentagon X2. All their lights feature interchangeable tailcaps and heads as well as double O-ring seals at all connection points. Their clickies are designed to be soft and quiet, a feature many dislike.
Without knowing exactly what you need I would say the best light for you to get from Pentagon would be the EX2/X2. It's cheaper than the LED based-L2 but can accept P60 sized lamp assemblies. This means that you can update the light with a Cree/Rebel based lamp assembly if you so desire. The stock EX2/X2 lamp assembly is typical incandescent, 1 hour runtime, about 60-70 lumens and bright/white light with a lot of throw. It's a good lamp but is generally outclassed by the newer LEDs.
The stock 3watt L2 LED light engine is totally outclassed by current offerings. It will produce @50-55 lumens for 1.5 hours of flat regulation on 2xCR123A batteries. Not very good compared to a Cree. The heads of the L2s are sealed and opening one to replace the lamp assembly is kind of a pain and usually leads to damage to the anodizing.
The one-cell Pentagonlight, the X1, is a relic to the cutting edge flashlight user. It's still fairly large for a one-cell light since it shares the same 27mm reflector as the X2 but it has the smaller output of a 3 volt lamp assembly. The output is around 35 lumens with a little over 1 hour of declining brightness. Beam profile is fairly balanced with a slight push towards throw. I purchased mine purely for collector value and other than for modding purposes I don't see a lot of use for this light, when compared to what one can get for a Cree light at around the same price.
I am unsure about their plans to update to Cree/Rebel but I can only assume they must be as some point in the future if they wish to stay competitive with thier main rival, Surefire.
Pics coming up.