@Jeffrey... I will agree with you that the Nikon D3100 feels better than the T3 in the hand. Actually the most solid-feeling entry-level DSLR out there right now is the Pentax K-r but that's beside the point. It does have more intuitively laid-out controls.
However I have shot with both the D3100 and the T3 and had a much more enjoyable shooting experience with the T3 than the D3100. The T3 seems faster in just about every aspect than the D3100, it has a better viewfinder, and despite its screen being low-res, I actually didn't think it was that bad and it's better than the D3100's. And it has impressive photo quality (even with the kit lens). I think Canon was smart to only have the sensor @ 12mp.
So I think overall the T3 is the better DSLR. However, I think Canon should be worried about the Nikon D5100 as a competitor to their T3i.
There haven't been any reviews of the T3 yet, but the Nikon D3100 definitely looks to be the better camera between the two. We just got the T3 in at the store I work at and if you actually hold it in your hands it's built out of a lot cheaper feeling material than I've ever seen for an SLR. I don't think specs are that important when it comes to cameras but the D3100 is better in those areas too, with 14 MP instead of 12, 1080p video instead of 720p, and 11 auto-focus points instead of 9. The D3100 has a $100 higher msrp but because it's been out for a few months you can get it for $600 or less.
The main disadvantage with Nikon is that it doesn't have an auto-focusing motor built into the body so it won't auto-focus with older non AF-S lenses. The Canon doesn't have an in-body focusing motor either but Canon's been building the focusing motor into the lenses since the 80's whereas Nikon started later and doesn't have as many auto-focusing lenses to choose from. The main beginner lens you would get for the Canon is the 50mm f1.8 which is only $100 and is sharper and works better in low light than the kit lens. Nikon has a 50mm f1.8 for roughly $100 but it won't auto-focus with the D3100, however they do have a 35mm af-s f1.8 lens which has all the same advantages as the 50mm but is actually better suited to (APS-C) digital cameras than a 50mm, which was designed with film in mind. The only drawback is that it's closer to $200 but you're getting a more modern lens with better build quality and a more useful focal length (unless you're shooting mostly portraits)
Higher megapixels is seen by many as a disadvantage, because you are squeezing more dots into the same sensor size. Even the full frame Nikons like the D3S or the D700 (which blow away either the D3100 or the T3) have 12 megapixels. I just watched a video review which confirms that in high ISO low light shooting, you are better off with the T3's 12 megapixel sensor than the T3i's 18 megapixel sensor. You will get a cleaner image at 12 megapixels. For me, I want a camera that can shoot really clean images at ISO 800 or 1600 at night. That is most important to me.
For me major difference was Canon having ISO 100 - 6400 for shooting from bright to dim light whereas Nikon D3100 only has ISO up to 3200. That makes Canon a much better option as far picture clarity in dim light is concerned. I do agree that it is 12 mp but that's not too less compared to 14mp. Major CONS of canon do include 720mp video but if video isn't that important, i would stick with CANON..
I'm thinking about buying new DSLR.. Nikon D3100 has been on top of the list and competing with Canon T3. Though, what matters to me is picture quality / colors / sharpness. I dont care much about video shooting as I can use my iphone when needed. My question is if anyone of you are professional photographer or has expirence dealing with both cameras.. which one would you buy? both are about at the same price. I need camera which can take nice outdoor pictures and perform better than point n shoot in low light (indoors).
d3100 doesn't support auto-exposure bracketing, which makes HDR photography a nightmare. Even the t3 supports it ... not sure what nikon was thinking except to keep some features for their higher end cameras.
Ended up buying canon T1i instead of T3... will be in my hands next week. Bought it from Walmart for 629. Amazon price was 709 for the same camera. Letting you guys know if anyone is interested in buying Canon T1i. it is a 15MP camera with 720p video at 30fps and 1080p with 20fps. I really don't care for video part but it was really good deal compared to what best buy or amazon was asking for same camera.