I think at this point in the century, everyone reading this blog—with the [possible] exception of certain lurkers who are required by virtue of their position within their company to toe the Party Line and therefore may not be free to say what they really think—is clear on the drawbacks of DRM.
But regional restrictions make me wince, because from an author's point of view the situation is a bit more complicated.
In principle, I oppose region restrictions. As a reader, they make me itch. But in practice, the way book distribution works across international borders is worse than imperfect: it's broken. If I sell world English language rights to one of my books to a publisher, that publisher can't just print and distribute the book everywhere in the English-speaking world. Publishers used to be regional, not global, players. And even in the wake of the wave of takeovers that resulted in the Big
Six Five owning about 70% of the business, mergers between publishing houses are incredibly slow and complicated due to contractual encumbrances. As a result, publishers generally don't have the branding, imprint, and corporate connections to sell books in more than one territory. Let me emphasize this: they're regional, not global, operations.[*] So if they find they've got publishing rights to territories where they don't have printing and distribution arrangements they generally sub-license the rights to other, local, publishers who've got the connections to sell books to the local trade channels.
This means that they can't offer me a bigger book advance for world rights than they would for their own regional rights (because they might not succeed in licensing those territorial sub-rights—this has bitten me in the past). If they paid a world-rights-sized advance for what turned out to be regional sales they'd make a huge loss, which in turn would make them very leery about doing repeat business with me. Consequently we end up with different editions published by local publishers at different prices, with regional distribution restrictions.
Also, when publishers sell sub-licenses, the contract side is generally handled by clerical staff who handle the sub-rights for hundreds of books a year, with no particular incentive for prioritizing my work.
Consequently I prefer to get my literary agent to split the various regional rights up and sell them separately, so I get paid for North American rights by my US publisher and UK/Commonwealth (except Canada) rights by my UK publisher. This results in more money for me. It also results in better royalty contracts—my agent takes a 15% commission, so the bigger the deal the more money she gets (and the more money I get).
But from a book-buying reader's point of view ...
This was fine in the old paper book days—books were uneconomical to bulk-ship internationally, and thanks to the first sale doctrine readers who really wanted foreign editions could legally mail-order them and pay for shipping. What the casual buyer doesn't see on the shop shelves they don't feel the lack of: so everybody was happy, more or less.
But in the age of ebooks, borders are increasingly porous. And Brits can see what is in the Kindle store on Amazon.com, and Americans can see what's in the Kindle store on Amazon.co.uk, and British and American publishers can see how each others' titles are doing. Regional publishers are jealous of their regional sales—nobody wants a big rival from another country to kick down the door and eat their lunch—so they enforce contractual terms on the ebook stores that lock in territoriality. The ebook stores for the most part are more than happy to go along with this: it gives them a valuable lever for selling their DRM-enforced walled garden model of ebook publishing to publishers. The walled gardens in turn lock end-customers into the e-book store's platform, be it Kindle or iBooks or Adobe Digital Editions.
So what started out as a natural side-effect of books being heavy and not worth shipping across oceans has turned into a royal pain in the ass for readers—but where the desired solution for the readers (global sales, a flat worldwide market) will cause significant pain to the authors in the medium term (and by "pain" and "medium", I invite you to consider how you'd reply to a proposal that you take a 20-40% pay cut for 3-5 years).
What I'd like is a publisher who could genuinely operate globally—that is, publish a single edition throughout the English-speaking world, offering advances for my books that reflected global sales potential rather than regional, and removing the need for regional restrictions and DRM completely. And indeed—you saw that [*] footnote asterisk up top?—such a global publisher exists within my field. But it's Orbit ... a subsidiary of Hachette, and while there are a lot of good things I can say about Hachette their corporate high-level policy makes DRM mandatory, no exceptions. (Digression: Don't be fooled into thinking that Tor are a global player. While Tor US and Tor UK are both subsidiaries of Macmillan, which operates worldwide, they are entirely separate companies. Turns out, sibling rivalry is a thing: they're as jealous of their regional rights as any other rival companies.) So right now I can have my books published without DRM, in return for putting up with lots of regional messing-around (which is why the new Merchant Princes omnibuses won't be available on paper in North America until the back end of this year, a year after their UK publication). Or I can have a single publisher who operates globally ... but insists on DRM. Shorter Charlie: you can't win.
Hopefully the situation will improve in the medium term—meaning before the end of the decade. But your guess is as good as mine. And this is by way of explaining why you'll see different covers for my books, and different prices and publication dates and ISBNs, in different countries. Globalization: nice theory, shame about the practice.