I measured from power-on until the Finder dock came up and then again until when the first application was running. The first application starts slower than subsequent applications because of the OS threads that are still running. I chose Chrome as that application because that is what I usually start first. Once the OS has settled down the applications start in sub-seconds to a second or two.
I installed the SSD first with a CCC clone and for some unknown reason CCC did not create the recovery partition on the SSD. Compared to the disk, that sped it up by a factor of two. I resorted to reformatting the SSD, installing Mavericks on it and the letting the Migration Assistant pull the files over from my old disk. To my surprise that sped it up by another factor of 2.5 for a total speedup of 5x from the SSD.
At the end, Chrome started so quickly that the wireless network was not yet up and the initial page load failed.
Having seen the 2.5x speedup from the clean install I experimented with a clean install on the disk and retested. I wrote zeros across the drive to map out bad blocks before installing Mavericks. This work made no difference in the boot time. I am at a loss to say why it made a difference on the SSD clean install and not on the disk install.
Do I need all that SSD speed? No. I don’t have I/O intensive applications or applications that cause a lot of paging. Upgrading the RAM sped up the applications and halved the boot time so I could have stopped there but I was used to faster boots on my MBA. This particular MacBook does not need a huge amount of storage so I felt I could afford a 120 GB SSD to make it go faster. If I had needed a 240 GB SSD I would not have spent the money. I hear the ~$110 hybrid SSD-disk options deliver a good compromise of speed and capacity but I have not measured them.
Ratios to original timings with 2 GB of RAM and a 5400 RPM disk less than half full:
Boot to Boot to
Finder Chrome
Dock Up
1.0 1.0 Original boot Time
2.7x 2.2x 2 GB RAM to 8 GB RAM
2.7x 4.0x CCC upgrade to SSD
8.0x 10.4x Clean install to SSD
Original timings: 120 seconds until Finder Dock and 240 seconds until Chrome loaded.
Final timings: 15 seconds until Finder Dock and 23 seconds until Chrome loaded.