Do higher-capacity SSDs last longer

Thanks James. It doesn't fully answer my question but there are some useful tidbits. To summarize some of the relevant parts of those talks:

SSD performance can increase by 10% or more as the "spare area" on the SSD increases.
Increases in spare area on MLC (vs SLC) is particularly good at increasing performance. Most of the SSDs which are reasonably big tend to use MLC, which has somewhat higher latency and lower write bandwidth, but comparable read bandwidth.

So drawing from this, it seems that a bigger SSD will probably have higher performance than a smaller SSD, unless the reason the smaller SSD is smaller is because it uses SLC or it has a higher percentage of spare.

This is mostly what I expected but it's nice to see confirmation.

Another useful but again not entirely comprehensive look comes from just scanning some of the tech specs on the web. For example I look a look at OCZ's page here on the Vertex Turbo. It seems that throughput does not come at all close to linearly increasing with drive size. It takes a jump from 30 GB to 120 GB to see a significant difference, and even then mainly for write speed not read.

3 is the answer. SSD controllers (and high-end USB flash drive controllers) are basically RAID controllers. This is one of the reasons that larger flash drives tend to be faster than smaller ones. Mobile devices usually don't have many flash chips and so their storage is slower.