David,
First disclaimer....I have no personal experience with the Balcar equipment, but I have been looking into some specs on lots of lighting lately. From what I gather, the Balcar Concept P4 (discontinued) is a 6400ws generator that can handle 4x1600ws heads. It is a 6-7 stop range, I believe, depending on the model.
The Profoto heads (ProHeads and Acute2/D4) are rated as 2500-3000ws heads, I believe. Most folks will not use them above 2400ws, but the ability is there when using a 4800ws pack, for example. Cannot comment as much on the Elinchroms, so somebody else will need to chime in.
On the monolight side of things, Profoto and Elinchrom do not have anything above 1200ws output units, I do not think. So you are immediately giving up 400ws total power with the biggest monolights from the others compared to the Balcar P4. There does not seem to be much published data on recycle times, nor light consistency from flash to flash. That is where Profotos really shine, and Elinchroms also hold their own.
Sorry if this is something you already know, but I did not know what part of the range you were most interested in....high ws output or other things. The Balcar 1600ws heads will pump a lot of light, so if you are used to working with that intensity of light, you may have to stay with packs and heads in Profoto or Elinchrom, as monolights will not get you there. The output in ws or Joules among these brands should be pretty consistent and reliable, so 1000ws in one should look pretty much like 1000ws in another. Recycle times on individual units may vary, but the light outputs should remain the same.
From what I have seen, a setting of 10 on the Balcar P4 is 100%, or 1600ws for each channel. Each step is one stop down, or 9 = 800ws, 8=400ws etc., down to 6 (100ws), which is the minimum output from the pack. By comparison, the Elinchroms and Profotos can drop down to much lower outputs, depending on the packs or which monolights are being used. Some will drop as low as 7-8ws output, which is not a lot of light, but useful for both very short duration, and for some table-top shooting where a lot of light is not needed.
Cannot offer much more than that, but others may have a lot more experience and knowledge to both add and correct any of my mis-statements.
LJ
PS. Caveat: this is all assuming that the Balcars are true ws or Joule outputs, and not the readings we see on some others, like White Lighting or Alien Bees, where there is a different ws rating from the "effective ws" rating. In Profotos and Elinchroms, if it says 1000ws, it is that, and not something like 600ws as can be the case with the WL and AB units.
PPS: Doing a bit more searching, and there is some question about the true ws outputs listing on the Balcars, much like the White Lightning and Alien Bee units. There is a difference in what is essentially the full capacity and the effective output. On the WLs and ABs, the "general formula" for correction is to divide the posted ws rating by 2.5 to get the true ws output. So a 1600ws WL for example, is closer to 640ws of light delivered by something like a Profoto or Elinchrom. That is a rough rule of thumb. Others may have more knowledge of this strange posting from the Paul C. Buff folks, and I do NOT know how that compares with anything from Balcar.
