Seems like the tests with solid state on the Windows side have not had much effect at shortening the boot time. It seems that although there is plenty of memory on the cheap, if you want faster boot times, you need to buy the faster memory. I've seen this SanDisk Extreme III mentioned as a good choice.
On the Windows side, to speed up the load and fit the OS into the chip, they use nLite to strip down the size by leaving out services they don't need. I haven't seen that done on OSX but it wouldn't surprise me if you could do the same.
It seems like the main reason for installing it is reliability and performance in low temps that affect the drives.