[mgmueller]

From time to time I'll give a brief summary of my momentary gadgets.
I'll add ca. 25 readers and ca. 35 tablets to this summary, my whole collection.
I can't give exact rankings (how to compare Kindle Paperwhite to iPad mini?), I'll stick to generalizations such as "top 10%".
I'll use alphabetical order.

Amazon Kindle Paperwhite
I've always been a fan of Kindles. I've bought almost all of them. I really love the free 3G, available globally! I've replaced my Kindle Touch by the Kindle Paperwhite and totally love it. I never had any problems with eReaders, didn't bother about the "grey (text) on grey (background)" as some describe it. But I have to say: "Paperwhite" is a valid description. Still perfectly readable in direct sunlight. But actually I mainly use it in bed, without any additional light. Some criticise the tiny blurs, caused by the lights. I don't mind at all. They are visible, but no distraction at all. I didn't have a problem with the lower resolution of former Kindles, but it adds to an almost perfect reading experience. Only complaint: Paperwhite only has 2GB of internal memory and (as all Kindles and lots of other readers) can't be expanded via SD card. Former Kindles did have 4GB. I've already exceeded the limit of 2GB. Amazon refers to the cloud, but I'd prefer having all my books on the unit all the time. I'm deleting the ones I've read recently and can live with that. Still: Why reduce to 2GB? I'd rather pay another 20 Euros or something like that and have my old 4GB back.
Ranking: Top 10% = Top 5 of my units.

Apple iPad mini
Surprisingly enough, my favorite iPad. Some criticise the missing Retina display. I don't have a problem with that. It's got the resolution of iPad 2 - on half the display size. Personally, I prefer 7" or 8" over 10", especially for prolonged reading sessions. All iPads have great battery life, especially in standby. Only problem I face: WiFi is relatively weak. In some rooms of my house I don't have any connection, although other tablets still connect without problems. The price, compared to Google Nexus 7 for example, is extremely steep, but totally worth it. I love the design, because of the size the curved edges are less obvious than on the bigger iPads. Compared to most other tablets, the design reflects the price. It seems more valuable and stylish than most competitors. And it has stereo speakers. I always found the mono speaker one of the weak spots of former iPads.
Ranking: Top 10% = Top 5 of my units.

Google (Asus) Nexus 7
I've sold my first one after a few weeks out of frustration. It was extremely slow and unstable, especially when handling lots of files (i. e. 700 Amazon books in the Kindle app or 12GB of magazines in the Zinio app). Someone mentioned, the new firmware did solve this issue. I took the risk and bought another one. Surprise: Totally stable and no slow-downs. No idea, whether my first one had been a "Monday" unit, whether it was the storage (I only had the 16GB version at first and had loaded apps close to the limit, now I have the 32GB one) or whether it's the new firmware. Anyway: For this price, it's a real bargain, even a game changer. And it's well enough designed. No iPad mini, but no complaints for half the price.
Ranking: Top 20% = Top 10 of my units, but probably not in the Top 5.

Kobo Arc
On BlackBerry PlayBook, I only had the Kobo app for a long time. So I bought about 250 books from them. That's the main reason, why I wanted to have a Kobo tablet (and a Nook and a Kindle tablet for the very same reason).
Kobo Arc, of all specialised (=manufactured/sold by a book merchant) tablets (including Kindle and Nook for example) is the only "open" one.
It uses stock Android. Even the Kobo app seems 100% identical to the "normal" Android one. I guess, it's a direct competitor to Google Nexus 7. Not only interesting for Kobo fans, but for customers looking for a "real" Android tablet.
Of course, with a bit of work, you can do the same on Nook or Kindle. But on Kobo Arc, you've got it "out of the box".
Ranking: Top 10% to 15% = maybe not in the Top 5 of all units, but at least very close.

Microsoft Surface RT
Some critics are extremely negative. I don't get it. The resolution is no Retina display, but I don't have any complaints at all. Colors are extremely vivid and natural. Not as over-saturated as on Samsung units. It may seem a bit "dull" at first, but I absolutely prefer it over the "candy" colors of many other tablets.
The combination of Windows 8 tiles and desktop isn't perfect. But for business use, it's lightyears ahead of Android or iOS. It's no clone of the others, it's the first "new thing" in tablets for at least a year (when HP TouchPad and BlackBerry PlayBook did introduce their respective OSs and unfortunately more or less have failed).
I love both keyboards. The touch one for traveling light, the type one for heavy business use.
The design is great. It seems about as valuable as iPads, ahead of the crowd.
My only worry: HP TouchPad and BlackBerry PlayBook do have great OSs and features, but they disappeared because the market lusts for apps. I certainly hope this won't happen for Surface RT.
Surface Pro will be able to handle the Windows legacy software, so this should be a safe bet.
Ranking: Top 10% = Top 5 of my units.