The first one is kinda boring, it took me around a year and a half to beat it. But the second one prove that it was all worth it, I've finished it in like a month and enjoyed almost everything it offered. The first one is just a long build up for the second, it has very good writing and good characters, but the story is your usual stuff presented in chunks, with little going on on a grander level. I am currently on the 3rd - it has much different approach, feels like fanservice for the moment, but I am not far into it.
If you are patient then its a great game, not on its own imo but because of the second part.
And turbo mode, every game should have turbo mode.