Preseed was a major mood killer for us and I think it made us feel too much like we were DTD to make a baby and not to enjoy each which in turn upps the stress levels and doesn't generally help conception. We only used it one month and conceived a couple of months after that when my cycle was better which I think was the real barrier to conception for us.
I'm sure it works for some people if your CM if the barrier to conception but I think you can fix this through diet too.