Running Benchmark AHB2 in bridged mode and 4 Ohm Speaker

No answer to the above claim.
All I can say to that is "if correct", that Benchmark should never have released this amp in stereo form, they should be all bridged, as the Stereo version is in some way hobbled and should not be purchased.

And there is no parameter that’s improved with bridging with this amp, except for and increase in wattage, and as Roger Mojeski said "it’s just a sale gimmick to sell more amps".

Cheers George

Lordcloud is not making a claim (an assertion without evidence). He is sharing the experience of using the AHB2 in Mono mode. 

George, let's suggest someone bought two parasound bridgeable amps, and they said they sound better in Mono mode than biamping.  Would you suggest that Parasound bridgeable amps are a sales gimmick to sell more amps, and Parasound, "should never have released this amp in stereo form, they should be all bridged, as the Stereo version is in some way hobbled and should not be purchased." 

I'm checking for consistency.  Imo you are making claims far beyond that of biamping versus bridged operation, suggesting that the AHB2 has been poorly designed or intentionally hindered to sell more units. To date I don't think you have provided one shred of evidence to support such claims. Frankly, I think you are walking on very thin ice with such claims against Benchmark.   :) 

Just noticed this on the Benchmark website: THE AHB2 IS SOLD OUT. ORDERS PLACED TODAY WILL SHIP ON OR ABOUT DECEMBER 7TH. 

There's a bit of anti-bridging hysteria on this thread.  I've run bridged, vertical bi-amp and regular and the idea that bridging is necessarily bad is silly.  Current certainly doesn't go down in bridged mode.  Watts are volts times amps and volts = amps times impedance.  An amp that can put 100 watts into 10 ohms, say, means that it is putting 3.33 amps at 33.3 volts into the speaker.  If you bridge it and get 200 watts into the same load the current has gone up.  In this case the formula for current is the square root of the watts divided by ten.  The current for 200 watts is the square root of 20.  For 400 watts it's the square root of 40, etc.  

Keep in mind, too, that the amp is only driving one speaker so it's not working as hard for the same volume.  There is certainly the potential for problems with low impedance loads but I've never experienced it.  I'm running two amps bridged mono into 4 ohm speakers now, have been doing it for 6 years and have never had a problem.  I like the option of being able to buy a second identical amp if the first one is a little underpowered.