So I went ahead and recommended Gokaiger to my friend. It turns out he did some research and watched the opening of every series plus the henshin sequences of every team and decided to watch whichever one caught his interest.

And his choice...Kyuranger! The suits and the large cast must have sold it to him. I did warn him that its rough around the edges and the fandom isn't exactly singing it praises, but maybe a fresh eye on Sentai will work for him. I don't know he might really like it.

His other choices were Go-onger, Shinkenger and Go-busters(and I tried selling Go-busters instead). He said he'll check them out after Kyuranger.

So I hope Kyuranger can make a covert out of him. It is what it is. Yosha lucky I guess?

*gasp*
GET YOUR FRIEND TO WATCH SHINKENGER
GET YOUR FRIEND TO WATCH SHINKENGER
GET YOUR FRIEND TO WATCH SHINKENGER

Ha ha! I tried believe me. I said to pick any of the other three but well... I mean he MIGHT like it, who knows.

I've watched Gokaiger fine without much prior knowledge to previous Sentai shows. I think the only thing you'd really feel lost on are the Jetman and Timeranger episodes but aside from that I think it's a good entry point.