So I've spent the last couple hours doing some research. At first glance, the Kindle Unlimited program looks like a beefed up version of the Kindle Lending Library. Only, instead of one book per month, you can check out ten at a time with no expiration date. They go away once you give them back but, as I understand it, you could hang on to them indefinitely.
The selection was my biggest concern. After some searching, I've found roughly 30 titles that I'm interested in. That's more than enough to give the free trial a shot. I've got horror novellas, some non-fiction, a mystery, and even some sf/fantasy. It's a pretty nice mix. However, I have noticed that the bulk of it seems awfully similar to the Kindle books I see in my various cheap/free ebook emails every day. On the flip side, Lord of the Rings and Harry Potter are both in the Kindle Unlimited program, a boon to me since I've been thinking of re-reading both of them.
The interface is a lot smoother than that of the Kindle Lending Library. You can send the book to your kindle from the book's page rather than going to the kindle store, a big improvement in my book. At $9.99 per month, the price sounds more than reasonable, provided I can find enough books that I want to read that are also in the program. I guess I can do the free trial and then opt out when it's time to plunk down money.
That's all for me. I have to figure out which Kindle Unlimited book I'm going to read first.