Consumer Reports Score
Abbreviated list
88 iPad PRo 12.9" 5G 129GB 12.9" 2022 $1,000
87 iPad 64 GB 2021 10.2" $330
84 Galaxy tab S9 Ultra 14.6" $1,200
84 Galazy Tab S9 128GB 11" $800
82 Galaxy Tab S9 FE+ $550
76 Galaxy Tab S6 lite 10.2" $200

Not check rated
71 Amazon Fire HD10 (Fire OS) 10.1" $90
69 Lenovo Tab M10 Plus 10.6" $198

See Tablets under Technology

See the eReader page for kindle, nook, ...

I've started including the phone-tablet hybrids (5-6" devices) here.

Note: Many new tablets were announced at the 2011 Consumer Electronics Show (CES), in Las Vegas. Google's Android OS was the most popular but there were devices with the Chrome OS and Windows 7.

As of March, 2011 the consensus was the iPad (now out with version 2) is still the winner.
The android devices have only a fraction of the apps optimized for tablets and have been buggy. They also seem to be expensive relative to the iPad.
In January, 2011 comscore announced that android phones accounted for 31% of the smartphone subscribers compared to 25% for the iPhone. Apples share may improve with their recent addition of the Verizon iPhone.
I think the android tablets will improve, but being spread across multiple providers (Samsung, Dell, Motorola, Toshiba) they will not have the buying power for components that Apple has.

2013 - Market

2013 - Devices

Model	Size	resol (px)	PPI	OS	CPU	Video player	RAM	Camera
New Nexus 7	7"	1920x1200	323	4.3	1.5Ghz quad-core Snapdragon S4 Pro	Full HD	2G	5MP
Sony Xperia Z Ultra	6.4"	1920x1080	334	4.2	2.2GHz Snapdragon 800	Full HD@30fps	2G	8MP
Samsung Galaxy Note 3 ?	6"?	1920x1080?	267	4.3	Snapdragon 800

2011-12

Model	Size	resol (px)	PPI	OS	CPU	Video player	Camera
202 Samsung Galaxy Note	5"	1280x800	285
Samsung Galaxy Note 2	5.5"	1280x720	267	4.0	1.5GHz Exynos four quad processor	Full HD@30fps	13MP
204 Nook Tablet	7"	1024x600	170
205 Amazon Kindle Fire	7"	1024x600	170
206 Lenovo Ideapad A1	7"	1024x600	170
207 HTC Flyer	7"	1024x600	170
Nook Color	7"	1024x600	170
Samsung Galaxy TAB 7 †	7"	1024x600	170	2.2	1.06GHz	Full HD@30fps	3MP
Samsung Galaxy TAB 7 Plus	7"	1024x600	170	3.2	1.2GHz dual-core	1080p@ 30fps	3MP
Samsung Galaxy TAB 2 7.0	7"	1024x600	170	4.0	1 GHz Dual-Core	Full HD@30fps	3MP
Samsung Galaxy TAB 7.7	7"	1280x800	196	3.2	1.4GHz dual-core	1080p@30fps	2MP
Samsung Galaxy Tab 8.9	8.9"	1280x800	170
Sony Tablet S	9.4"	1280x800	159
Acer Iconia Tab A500	10.1"	1280x800	149
ASUS EEE Pad Transformer	10.1"	1280x800	149
Lenovo Thinkpad Tablet	10.1"	1280x800	149
Toshiba Thrive	10.1"	1280x800	149
Apple iPad 2	9.7"	1024x768	132
New Apple iPad	9.7"	2048x1536	264
Google Nexus 7	7"	1280x800	216	4.1	1.3Ghz quad-core Tegra 3	1080p@30fps	none
iPad mini	7.9"	1024x768	162		A5

Source: AllTouchTablet.com

Reviews:TechRadar | c|net

Screen sizes on NetBooks and Smartphones:
An Asus 10.1 in Eee PC 1015PE netbook is 10.3x7.1x1.5 2.7 lbs with a 1024x600 display.
13" MacBook is 13x9.1x1.1 4.7 lbs with a 1280x800 display.
An iPhone 4 has a 3.5" 640x960 display, A Droid X has a 4.3" 480x854 display

† Costs:
I can get a Samsung Galaxy Tab from Verizon for $200 with a $20/mo. 1GB data plan.
The net present cost of $20/mo for 2 years at 4% (Rate on my home equity loan) is $300.
So the total cost is $500.
I can get the Tab without a data plan at BestBuy for $430
I can subscribe to the data plan on a month to month basis, but it costs an additional $35 each time I re-initialize it after disconnecting.

Consumer Reports:
9-12 inch
the 4G iPad and Samsung Galaxy tab 8.9 got scores of 83-85
The Asus Transformer Prime and iPad 2 got 82's
The Wi-Fi only Samsung Galaxy tab 8.9 and 10.1 got 80-82
Acer Iconia Tab A700   80
Lenovo IdeaTab S2109    80
Motorola Droid Xyboard 10.1  79
Toshiba and Sony got 79
Acer and Asus Eee Pad got 75's

7-8 inch
Samsung Galaxy tab 7.7 got 79
Google Nexus 7  (no camera)  got 79
Samsung Galaxy tab 7.0 got 72
Samsung Galaxy tab 2 7.0 got 76
Toshiba Thrive 7" got  69
Amazon Kindle Fire got 66
B&N Nook               62

* A suit jacket pocket is typically 6" wide by 7.5" deep.
My casual jacket pocket is 5x6. My soft shell and fleece vest pockets are 8x6, and my fishing vest front pocket is 7.5x4.7 .
The back pocket on my Gregory backpack is 7.5 x 10.

1. Assisted GPS (A-GPS) - A GPS system that uses network information (e.g. cell towers or WiFi location from a database of IP addresses) to help the GPS acquire satellites faster.

2. QNX Neutrino RTOS - A is POSIX-certified OS. POSIX is the Portable Operating System Interface [for Unix].

Camera Resolution:
 Phones
  iPhone 5               8Mp
  Samsung Galaxy Note 2  8Mp
 Tablets
  3rd gen iPad   5Mp
  Galaxy Tab 7   3Mp
  Nexus 7 tablet 1.2 Mp