Hi all. Regarding the bent lip bed knife. I have had one on my 14" SB for about 2 years now and I don't notice any difference to the cut, however as my reel had run out of adjustment due to the reel been sharpen many times, by changing the flat bed knife to the lip type allows you to raise the reel up by around 10mm. This then prolongs the life of the reel.
At first I thought the bent lip would restrict at how short I could cut my lawn. But it doesn't. My back lawn is couch and I can cut it very short. I doubt bowling green height, but short enough for home lawn.
Also, to add to the can of worms, I prefer to have slight contact. If you google this there are many websites that are for and against this. As said, it's all down to what makes you happy.