Aaahhh yes.....here's what a fellow CL member who has both a 450h and IS-F had to say about this specific point....

Originally Posted by timeToy
I have a '07 GS450h (that I trying to sell...) and just moved to the '08 IS-F. Thanks to the Hybrid power train the GS450h has a fantastic pick-up, linear, silent, powerful, it is really hard to match or beat it, the GS 450h has a lot of power from 20 to 50 or from 60 to 80, but that about it, you will be able to accelerate very hard for 4 to 6 seconds, not more...
"

Based on his observations, using the electric boost provided by the hybrid package CAN discharge enough to where the 450h becomes nothing more than (possibly) a heavy GS350.

 

actually even in nascar there are still tons of braking

 

It's been a well documented complaint by both C&D & MT for the 450h on their review tests. Both these rags have a huge man-crush on the 3 & 5 series, but the flaw is there, now will 95% of 450h owners ever reach this point is the true point to doubt...

 

very well put

 

thing is - motor recharges the batteries as well, so when you brake, not only brakes recharge them, but petrol engine as well, so they should get energy back pretty quick...

of course, not if you are racing on some very long straights, there engine would have to be a lot more aggressive when recharging, which I dont think it is currently...

 

It does seem to keep itself recharged especially well. Most notably when coming down a mountain and you get all 8 bars of charge, it will operate electric olny on the highway at 65 but only when it has a full charge. Honestly I can't think of a place I would take a midsize sports/luxury sedan where I wouldn't brake for corners and recharge the batteries. Even when the batteries do get down to 2 bars, (when your sitting in traffic with AC and radio) you still are left with a little less than a 350 and that is pretty good!