Thing is, Sharp tests are standardised tests - unfortunately however, there's no such thing as a standard accident, so there's no telling how a particular lid will fare.
Also, there's no detailing how much of a difference there is between star ratings - ie, if you have a 4* lid, has it only just scraped past a 3* rating, or is it just short of 5*? 
The best lid is the one that fits well and is comfortable - a 3 or 4 star lid that fits is better than a 5* one that moves (or comes off) in a spill, equally, one thats too tight can be uncomfortable which distracts from your riding - and if you become distracted, you may well find yourself putting that helmet to the ultimate test.....
I had one of those Duchinni lids as a stop gap, and whilst its quite comfortable physically, I found it admitted a lot of wind roar (I think it was just about the worst one I've ever had in that regard). Not likely to buy another anytime soon.