ive had a blue top for 2 years, discharged it to what would normally be 'beyond salvage' @ 5 volts, recharged it slowly on a power supply and now its fine again, and im yet to see any other battery that can crank an NA for 5 minutes straight with more to spare.... and even at $AU400 they are still worth it I think... maybe all the other batteries we get here are cr@p :p I always recommend Optima batteries anyway...