You would loose TRIM, which, depending on what you are doing, might matter, or it might not.
Traditionally RAID was about spreading out the IO requests to mask latency and while the latency of SSDs is a lot lower they can still benefit from this. But that does require a RAID solution that adds very little latency. I suspect most RAID cards will add more latency than you gain by this and thus end up hurting performance.
RAIDing SSD does scale the throughput very well. RAID-0 of two SSD effectively doubled the throughput. So anything that is limited by throughput would greatly improve from RAIDed SSDs.
As for RAID-10 vs RAID-50 I would go with 10, simply because I suspect that even a really beefy RAID card would end up a bad bottleneck due to the parity calculations, especially in smaller writes.