We used pre seed when TTC we'd been trying for about 12 or 18 months I thought it was worth a go seeing as DP had low sperm count anything that would be more sperm friendly was worth a try
Having said that the month we conceived we hadn't actually used it.
It was good stuff though not like your normal lubes I can be really sensitive to things like lube and had no irritation with it.
I have heard other posters on BB swear by it for ttc.
It's not cheap though so it's wise to use only on your most fertile days to save $$

Good luck whatever you decide