Some, or most, of the problems reported with any camera is largely due to user error and not the camera. So take that with a grain of salt. Most are not worth the electricity to run your computer. There are plenty of 70D's out there that are working beautifully.
The very last place is Amazon.
I agree with ebiggs that it's likely the vast majority of "problems" with 70D focus were actually due to new users who were using the AF system incorrectly. The 70D uses an AF system very similar to what was pioneered in the original 7D five years earlier... and we saw an awful lot of the exact same complaints when that camera was introduced. In fact, I upgraded from much simpler 50D's to a pair of 7D's and had a steep learning curve with the much more complicated AF system myself. But once I learned to use it, I get faster and better results than I ever did with earlier Canon models.
Just read up on the 19-point AF system of the 70D and learn to use it properly. Odds are very good that once you do that, you'll be quite happy with the camera. In fact, the 70D has an edge on the original 7D, with a more advanced form of the Micro Focus Adjustment feature.
I do not share ebiggs concerns about Amazon. In fact I've bought a lot of items via Amazon (as well as B&H, Adorama, etc.) and haven't had any problems what-so-ever. I believe Amazon Direct (as opposed to one of their "sellers") is an official Canon dealer, with competitive pricing, full warranties and a liberal "no questions asked" return policy, much like the best retailers. What Amazon lacks is much sales support... There's essentially no employee there to ask questions of (though there are reviews and means of asking questions of other buyers of specific products). A local retailer or one of the large, well-established online etailers will usually have knowledgeable people available by phone, email, IM/text, etc. to answer questions in detail. Amazon doesn't have that... it's essentially a warehouse and shipping operation. Still, that can work out fine, so long as you do your homework (as you appear to be doing).
I don't use one myself, but the EF-S 18-135mm seems a good, reasonably versatile choice for starters, too. And it's even more of a good value when bought in a bundle with a camera. Be aware there are actually two versions of the 18-135mm.... a slightly lower priced one with a micro motor focus drive system and an "STM" or "stepper motor" version that usually costs about $50 more. The STM focus drive lens is a bit faster and smoother focusing, as well as quieter. It's a better choice if you want to shoot video, in particular, but also is a good lens for still photos. I would further recommend you get the lens hood for the 18-135mm, which is not typically included (might be in a bundle, though... so check).
There are "official" Canon bundles and "retailer assembled" bundles. The official bundles are reliable. The retailer bundles you have to be a little careful of... Some are good. Some are not because they might substitute a cheaper lens, withhold an important item, or load it up with fairly junky accessories that have little value. OTOH, some of the more reputable retailers put together very nice and useful bundles that are good values.
A "proper" bundle should include everything that the Canon website shows is "in the box" with a camera and lens... and a retailer assembled one may also include other things the retailer has added. Beware of retailer bundles that subtract normally included (and necessary) items and then try to sell them to you at inflated prices. Some of the more extreme "deals" on the Internet actually turn out to not be a very good bargain, using those sorts of tactics. In other words, if it sounds too good to be true, it probably is! You won't see this happening with offical Canon bundles, Amazon Direct and other official Canon retailers, though.
Some bundles include a memory card or extra batteries. If the one you are looking at doesn't, you might consider those, as well. You'll definitely need at least the memory card.
I also highly recommend getting one of the guide books specific to the camera, to help you get up to speed with it as quickly as possible. There will be an instruction manual provided, of course (might be on disk these days), and that will be a big help. But the various guide books take it a step or two farther, explaining what, why and how to do things with the camera. Any time I get a new camera, I always get one of the guides to shorten my learning curve! (I wasn't able to with my 7D's, because they were so new on the market that none had been written yet.) I'm sure there are many good ones, but I can vouch for the guides written by Michael Guncheon, Charlotte Lowry and David Busch, from personal experience with their books. If you are completely new to SLRs/DSLRs and/or photography in general, I highly recommend Bryan Perterson's "Understanding Exposure", too.
Canon will sell the camera as a "body only" (no lens) or you can buy a kit which will include typically one lens (and sometimes two).
Amazon sells products on their own, but they also have a "marketplace" where 3rd party merchants can sell products. It's those 3rd party merchants who will create bundles which are often (usually) loaded with junk-grade gear that an experienced photography would never waste their money buying.
They might throw in a tripod, filters, bags, and even "lenses". The lenses are the worst. They aren't lenses in the sense that they are designed for your Canon camera. They screw on to the filter threads that a true lens has to alter the image (wide adapter, telephoto adapter, etc.) But their quality is so awful that you'd get better results with a point & shoot or camera phone (you may as well not buy a nice DSLR camera.) They usually have poor build quality and I've encountered numerous threads in which the unsuspecting camera owner screws the adapter onto the lens and subsequently discovers the threads have jammed and they can't get it off. Some of these literally break apart when the owner tries to remove it. I've encountered at least one thread in which the owner had to mail away their lens to service to have the adapter removed.
Amazon doesn't directly offer these types of bundles... you typically only find them from marketplace merchants, eBay merchants, and some fly-by-night camera shops with poor ratings.
If buying from a merchant such as Best Buy, I would avoid the "extended warranty" that they offer. I've encountered numerous threads in which a Best Buy customer purchased a camera with "extended warranty", subsequently developed an issue which would be covered by warranty, and then had an absolutely awful time trying to get Best Buy to make good on the warranty. (I should mention that the warranty is generally yet another third party -- not Best Buy directly. Best Buy merely "sells" the warranty and takes a cut of the profit.)
The problem with extended warranties is that all the money is up front. If they sell you the warranty, they've made their money. If they actually have to honor the warranty, they start giving back that money (and/or losing money) and they are not very eager to do that. They seem to hope that they can frustrate the consumer into giving up.
It's my own opinion that if every time you are offered an exteneded warranty, you take the price of the warranty and deposit it into a savings account instead of buying the warranty (and you do this for EVERY product you buy... phones, appliances, electronics, etc.) then when the 1 out of a 100 products actually does fail, you'll find your savings account is positively flush with the cash needed to replace that defective product (with a lot of extra cash left over). Extended warranties are generally always a poor investment.