Bifidus' Doujins

After going through various hentai artists Twitter pages, it seems like Bifidus will be making a return to Shitsurakuten next month. So I decided to look through his/her artist page here and I noticed a fair amount of doujins. The preview images and the comments all seem pretty positive for each one, so I'm considering buying some but I'd like to get more opinions.

So if you bought a Bifidus doujin, what did you think and why? Which one(s) did you buy? Are they worth the cost? Would you recommend any in particular? If you bought more than one, which was your favorite?

Thanks!