I'll state upfront I consider my experience a bad one (but I'll save the personal stories for another day). Here was an issue I saw while training Sun staff on how to user MySQL:
Sun's has a conflict of interest in selling hardware.
MySQL (InnoDB) doesn't actually *work* on big computers. It only scales up to about 4-8 CPU cores, and then it hits all sorts of internal bottlenecks. Most architectures work around this by using many small machines rather than one big one (aka "scale out").
But for Sun the profits are larger on selling *bigger* hardware. Most of Sun's bigger hardware (SPARC) has many more CPU cores, but each of these cores are infact slower than most Intel/AMD cores. So it doesn't work.
I'm not sure that the "old guard" of Sun Sales people will take to selling smaller, lower margin systems. I can predict them still trying to continue to either sell bigger machines (and suggest deploying Oracle), or sell bigger machines that are actually unsuited to MySQL. I remember hearing a Clayton Christensen talk on when Intel launched Celeron - and they sold them out of a completely different office. That sounded smart.
I think the idea of using commodity hardware installing DRBD+Heartbeat was the hardest to explain to Sun employees in HA classes. They didn't see why someone wouldn't buy a $5,000-$10,000 SAN and be done with it (Note: I should point out DRBD has other advantages besides being a low-cost SAN replacement).
 This review is just one example. The analysis is even more interesting.