Neither, I think. I would get a single larger SSD with trim. The reason is that a larger SSD will have more nand chips inside. That lets the unit access more of those chips in parallel. Sort of an internal raid-0 if you will.
The value of a SSD is the miniscule access time. Most of what we do is small reads and writes so the maximum transfer rate is only if interest to synthetic benchmarks, not actual usage. As siminlal said, the value of trim is in keeping the write performance up.