Canon 70-200 f4 Is or 70-200 f2.8 ???????

I have used the canon 70-200 f4 lens for the past few years and upgraded to the IS lens a year ago. I looked at the f2.8 version but thought it was to heavy and kept the f4. I was in a camera shop the other week and had another look at the 2.8 version. They said they would give me a good price and it was that good I bought it. I have used the 2.8 version at a few weddings and still think its to heavy for me hand holding the camera at low shutter speeds...but I have now started using a monopod with the 2.8 lens and use it for Bride/Groom formal shots and some groups. The quality of the 2.8 version is different to the f4. When i say quality I mean background bokeh (blur). I love it. Which would i buy.....both is the answer. The f4 for general candid photography as it zooms so quick with the flick of the zoom ring...its ideal for candid reportage photography. The 2.8 is ultimate quality and works well when you have more time to spare...stopped down to 5.6 the lens is amazinglyy sharp and the bokeh is great. I will be keeping both.

rb