Said I was going to do a review but as I look around at other reviews I see the same things I would mention being said over and over. I have nothing new to bring to the table other than comparing it to the Pandora. So in shy of a full review I'll just give some impressions after a week or two of using it constantly.
Feels awesome, you get used to the weight real quick, can play for hours upon hours in a row without fatigue or discomfort. Controls are fantastic, not the best of the best, but the best all in one. The Pandoras dpad is still the best but the shields other controls are all better than the Pandora. Also ergonomically it's much superior in my opinion. The pandora is more mobile because of it's size, but I don't find it to be a big challenge to carry it along with me. Durability is defiantly in favor of the shield, it's a tank and has very high quality plastics the pandora has "good enough" plastics but is completely fragile in comparison.
Get retroarch and the vast majority of your emulation (PSX, SNES, NES, GBA, GBC, VB, PCE, NGP, SMD, SMS, SGG, 2600 etc etc) will be dreamlike goodness. Drastic offers the same level for NDS. N64 & PSP are about the same level of playability with some games working remarkably well and others are just not compatible or too slow or glitchy to play. Given the brute power of the device its a much better experience on the shield vs the Pandora. I am still in the process of getting a 139 romset to test MAME but others say mame4droid reloaded is great. There's a select few ROMs that are supposed to give the system a challenge that I promised I would test. The tip of the hat to the shield for game console emulation because it has the power to push perfect framerates even with all the fancy filters and scalers enabled and even in more primitive emulators PSP, N64, Saturn etc, it can push them harder to get framerates not achievable on the Pandora.
The area the Pandora has the shield licked is computer emulation. Game computers (Amiga/c64 etc etc) and qemu are just natural fits on the Pandora where it's possible to do some of those systems with great or lots better actual performance but getting them to run is an absolute pain in the ass in my opinion and using them even worse. This is where having a on screen keyboard is no substitute. Storage is another strong suit of the Pandora with a practical max space of 256GB vs the shields current 80GB (less usable) 64GB micro + 16GB onboard. Battery life for emulation has been consistently the same 10 hours that I used to get on the Pandora with the same conditions (all radios off & half brightness) The vast majority of the emulators you find on the Pandora have similar ports on android and in some cases are ports of the same software.
Full support of Android vs Linux is the obvious difference here and could honestly be changed or converged upon on either device with either device fully supporting both OS's in a dual boot situation. All it takes is a community project or dedicated skilled developer on either or both devices. Full controls (analogs especially) in android games that support it is a major tip of the hat to shield in that respect. The Pandora has a lot of exclusive games that haven't been ported to android yet so the shield lacks a bit with the sheer number of games and apps that actually take advantage of all the controls and would benefit a lot from Pandoras software catalog if a Linux port were to be done. But the android games that the shield does play natively are unplayable or nowhere near as good on the Pandora with its unfinished android port or lack of power, or a combination of both.
As far as comparisons of the two devices aside from the price difference where I won't talk about because of the production scale of the two. This feels to me what the pandora 2 should be, or at least share a lot of the same qualities. Lots of
things people have been asking for in the pandora 2 are what are already in the shield. I'm not sure if this is a positive, but this looks like what craig's Pandora 2 would be if it had a keyboard attached. HDMI, rock solid wifi, higher def screen, R2 trigger buttons, microsd slot (not sure if a positive) Real analog sticks, quad core cortex a15 processor, 2GB ram (I think he wanted 8GB) these are all things people have been asking for and this has those things. This already has a lot of the things the pandora has as main selling features and does a lot of them one better. Minus the keyboard, and the OS it runs, this shares a hell of a lot of the similarities as the pandora even down to the clam shell design. That can't be overlooked.
Haven't gotten a chance to use the PC streaming yet or the miracast but those add a whole other aspect to the functionality that the pandora doesn't have. One allowing the shield to display what another machine is processing, and the other being another machine displaying what the shield is processing.
Think that sums up the subject at least in my opinion.