My first VN was G Senjou no Maou..
Being a fan of anything with a good storyline (movies, manga, anime, game, series, anything), it was quite an eye opening experience for me.. Reading an eroge is just not the same as watching movies or TV shows.. It just does not give you a feeling that you are in the protagonists shoes, you actually are the protagonist itself, and it just blew me away..
As for my first experience (*ahem), I would say the amount of time I allotted was worthwhile, and I think had it not been my first VN, I would still be hooked on whatever I tried first (my choices were FSN, which I almost played, and Clannad, which I learned thereafter was extremely long, so I saved it for my second one)..
And after my first experience, and a lot more, I've become addicted ^^