I didn't mention ethics, only pride and taste.

Well, your friends aren't getting paid, and if you explicitly declare that you want their honest opinion, and that a bad review would in no way impact their relationship with you, then there's no ethical problem.

Ethics only becomes an issue where you're paying someone to be dishonest about your product.

The ethical issue here is that a review should convey the good-faith impression of an unbiased user.