You can only borrow a single free book per month. If you want to borrow more you will probably have to pay.

In that case, it sounds like a nice bonus for Prime members, but I'm not going to pay $80/year just to get one free book for a month that I have to return later.

Of course you don't pay $80/year just to access ~$120 worth of book content. You pay to also get free 2-day shipping, a large library of free streaming videos, and what we can assume will be a growing pile of other benefits as time passes.

In the UK prime is bittersweet. Here all we get is free 1 day delivery.

That alone is pretty good - and for a "power user" of Amazon like me (who used to spend multiples of the £50 prime membership in delivery a year) it rocks.

But we don't get any of this good stuff (streaming/books).

Which is a shame because I suspect it would finally convince me to buy a Kindle :)

Less than a year ago, all you got in the USA was free 2 day delivery.

Licensing videos and books is surely very complex legally, so starting more than one country at a time would undoubtedly be very hard.

I'd hardly call that "bittersweet".