Book Promotions on Librarything ?

I've used them a few times. Initially I gave did a coupon code for smashwords. Which did give me a few reviews there, but didn't help much with Amazon. Eventually, I changed to gifting through Amazon when I knew I'd have a 99cent promo going. That way I would also get "sales", so some of my money came back to me, and I had a boost in ranking. Do it that way though you need to be careful. State clearly that it is gifted through Amazon, and before gifting to your winners, email them and ask them to confirm that that is the email they'd like it gifted to. Some people will enter any and everything and won't claim the gift. You also have to be prepared for a few of them to use the gift to purchase a different book.

Reviews are hit and miss. Maybe about 20% review the books they win.

not necessarily. There are a lot of people who don't realize that reviews help authors. There are people who don't have the time. There are also people who just have no interest in reviewing. Until I started writing, I never reviewed books.