Is MySQL ready for Prime Time

I've had a lot of experience with Oracle, SQL Server and Access. And now that I've explored LAMP and bit I see that many people are excited about MySQL. When I look at MySQL I find a lot of quirks - two engines ISAM and InnoDB - each with their benefits. I see their user management - again quirky. I wonder to myself, is this really ready to run the enterprises of large companies?

Is MySQL really ready for Prime Time?