As you may know, I try a lot of apps every week. Perhaps that is wrong, as one may be tempted to constantly jump between different softwares just for the sake of having something new to play with (like kids are always attracted by new toys), but I’m firmly convinced I’m doing this because there are hundreds of indie developers that don’t have the resources or the knowledge to virally promote their apps, yet they deserve attention.

That’s why I’m doing this. And thanks to this “method” (or habit), every once in a while I discover gems that redefine and refine my workflow. New apps that set new standards and raise an already high bar. It’s not easy. But it’s possible.

When it comes to PDF readers, however, the bar is so high, the alternatives so many and the standards so well-established that it’s not easy to come out with an innovative and powerful product that will make people jump from the app they’re using to a new one. Especially on the iPad, widely regarded as a perfect reading device, users have been struggling in the weeks after the tablet’s release date to find the ultimate PDF reading app; many fell in love with Good Reader and some of them eventually jumped on the updated iBooks bandwagon. PDF reading apps, though, are just a part of the story: annotation is where the money’s at. It turns out students and “pro” users wanted to able to read, organize, upload and annotate their PDF documents, not just read them.

With limited sync features, lack of external services support but overall fast rendering engine, iBooks provided a good alternative to the plethora of Good Reader-like alternatives, but it’s not exactly the most popular apps among PDF die-hard gurus.

So what I was looking for was a single app capable of pulling documents from Google, MobileMe and Dropbox, rendering them (even the large ones) with a crazy-fast engine and letting me annotate them. We’re overwhelmed with alternatives, but now that I’m getting serious about saving stuff in a huge PDF archive (more on this in the upcoming weeks) I want a single app to stick with and forget about the features I could get by combining 3 or 4 apps (people actually suggested this to me). I want a single place to come back to read and do things with my PDFs.

Meet PDF Expert for iPad.

PDF Expert, developed by App Store all-star Readdle, can edit documents stored on Google Docs, MobileMe (iDisk) and the usual Dropbox. I normally store documents on the latter, so I’m perfectly fine with the features offered by the app. As you can guess, it also supports iOS’ “Open in…” menu and email sharing – two options I’ve come to love since DEVONthink released its official iPad companion app (and again, more in the next weeks). Last – speaking of “minor features” – you can also protect documents you don’t want other people to mess with. Documents can be transferred using iTunes’ file sharing menu as well.

The reason I’m sticking to PDF Expert for my PDF needs, however, is very simple: it combines a fast engine with unique annotation tools that can be carried over to the Mac. PDF Expert takes seconds to open large PDF documents (tested with a 546-pages ebook, 30MB in size) and scrolling through them is equally fast and smooth. Unlike Readdle’s past App Store experience (ehm, Readdle Docs), PDF Expert comes with a polished UI (they can’t get that download menu right, anyway) especially in the actual reading section. If you tap on the screen when reading a document, in fact, an elegant and unobtrusive white bar will appear at the top with buttons to search for text, add a bookmark, share and annotate. PDF Expert’s UI is great because it doesn’t get in the way and doesn’t distract from what really matters: reading.

While there’s not really much to add about the app’s fast engine (I mean, it’s fast – what else is there to be added?), a few considerations need to be made about the annotation tools built in PDF Expert. I haven’t tried the ever popular iAnnotate PDF ($9.99 in the App Store), but the screenshots alone seem to suggest it’s not exactly the app for me. If annotation needs to be built-in, the it’s got to be integrated with iOS’ default reading and highlighting experience. I don’t want a standalone ugly UI just to highlight and underline some text. So PDF Expert puts everything you need  inside iOS’ default popup menu and that’s it. You highlight some text, you tap on the Highlight button in the menu and boom - your text’s got a nice yellow shade on it. Colors can be changed in the settings. Same applies for underline, strikeout and note: you tap and hold, the popup menu appears and then you do stuff. I haven’t got God knows what huge annotation requirements, but I enjoyed being able to tap and add side-notes to my PDFs. The opening animation and UI for notes are cool, too. Those notes and highlights can’t be viewed in other iOS apps (Apple’s limitation), but they render just fine on the Mac with Adobe Reader and Preview. Perfect.

So why am I using this app, while I could get the same features in other apps or Apple’s iBooks itself? PDF Expert integrates a powerful reading engine with great annotation features that work for me. I also appreciated the fact that DEVONthink for iPad and PDF Expert can “communicate” with each other when PDF Expert sends a document already stored in DEVONthink. DEVONthink will update its library but won’t display annotations, which like I said render just fine on the Mac. I like PDF Expert “integrated” model, and I don’t see switching to another app anytime soon.

Readdle released a fast and powerful app to read, organize and annotate PDFs. At $4.99 in the App Store, if you depend on PDF documents in your daily workflow and you don’t mind having the option to combine a fast engine (yes, faster than iBooks) with online services support and annotations, than this is the app for you. Go download it.