Two major advantages of LE over StartSSL:

1. certificates can be renewed before the old one expires
2. free certificate revocation

I value being able to renew the certificate early (no downtime) and I don't think StartSSL can do this.

In case the worst happens and I have to revoke, then at least it's not going to cost me money to do so, though I think it's only ~$10 for StartSSL.