If I'm reading the spec sheets correctly, the Yellow Top has the edge over the Red Top associated with slightly lower internal resistance and deep cycle capability (meaning it can be discharged to a lower voltage without incurring damage; the low limit is about 10.5V). The Odyssey PC2150 is also deep cycle and has the lowest internal resistance of the three. I am currently using both the Odyssey and the Yellow Top. The Odyssey sounds faster, more dynamic, more resolved-- a clear step up. It is about twice the cost tho ($250 at batterymart.com)
Hope this helps.
Red Top:
http://www.optimabatteries.com/publish/optima/americas0/en/config/product_info/automotive/starter/technical_specs.html
Yellow Top:
http://www.optimabatteries.com/publish/optima/americas0/en/config/product_info/automotive/deep_cycle/spec_sheets.RowPar.0001.ContentPar.0001.ColumnPar.0004.File.tmp/D34_082104.pdf
Odyssey
http://www.odysseyfactory.com/specs.htm
