For Father's Day I got the Eggware Vented Chimney Cap (http://eggware.net/). In my opinion this is a much better top than the standard BGE daisy wheel. The top of the cap rotates to adjust the airflow and it is made of the same material as the sliding vent on the bottom.
If you are interested in purchasing this cap enter the coupon code MIKE and you will get an extra 15% off.
Since the cap is made of stainless it will not rust like the daisy wheel. It is also supposed to be dishwasher safe. Worse case is I will break out the Bar Keepers Friend to clean any stains on the outside.
The top comes with a gasket so fits the Egg and will stay in place when you raise the lid. That was always my biggest grip with the daisy wheel. If you left it on the Egg when you opened it the diasy wheel would either slide open or fall off. That will never be an issue with this top.
I have already done multiple cooks with the new top. Once you get the temperature adjusted the top will After 12 years with the daisy wheel there are definitely some learnings for me. We the daisy wheel I knew the exact positions for both the top and bottom to hit a precise temperature. I am sure that will come very quickly with this top. It is very easy to adjust.
I have done cooks ranging from 300 to 550 and the cap has maintained the temperatures and performed very nicely. I have not done any 800+ degree cooks yet so we we see how the gasket holds up. They have a high temp gasket if need be that I heard performs very well http://www.nakedwhiz.com/productreviews/eggware/eggwarecap.htm
I would definitely recommend this cap to anyone who has the Egg or any other model this top will fit. My personal opinion is the Egg should look into making this standard.
One word of warning is this top gets much hotter than the daisy wheel. just use over mitts or tongs and it works just fine.
For the daisy wheel I left it in the egg for 30 minutes at 550 to cook off 12 years of grime. Once it cooled off I scrubbed it with an SOS pad sprayed it with a coat of olive oil and put it back in the egg for another 30 minutes. As you can see below, I have a little more work to do but it is coming along nicely for a 12 year old top.