I planned on using this tool as my primary GTD tool both project and non-project. I'm using a PC. I haven't really explored OmniFocus but will take a look at. Since Evernote seemed to be the most popular tool, I was wondering if 8.0 resolved a lot of issues that GTDers had with the product in the past.
I'm not sure what you mean by "a lot of issues that GTDers had with the product in the past." Some people like Evernote for GTD (like me), some others don't, and still others have never used it in the first place. Opinions will run all over the map. I think the best thing I can tell you is that it can work for you, but whether it will work for you depends on your personal preferences.
Again, Evernote 8.0 is the newest version on iOS. The Windows and web clients remain unchanged. So if someone didn't like Evernote for GTD before, I doubt the iOS redesign would do much to sway their opinion. After all, people are unlikely to use an iPhone or iPad alone to manage their system.
I like Evernote because it meets what I believe are the key criteria for a GTD list manager: it enables organizing of lists into buckets (I use notebooks for next actions, projects, waiting for and someday/maybe lists); it is portable since it syncs easily and is available on my PC, iPhone, and iPad (there are also Mac, Android and web clients although I don't use the first two platforms and rarely use the web client); it allows due dates via reminders; and it's easy enough to use that I don't have to think about it. And finally, I find it to be a versatile tool that I really enjoy using.
Some people don't like the fact that Evernote does not provide an easy way to link projects to next actions, which is not a necessity for practicing GTD but for many it's a strong preference. Some people don't like Evernote because it's not designed for GTD like some software applications, which means you do have to do some set-up (although it only took me about 10 mintes). That's not an exhaustive list but those are a couple of the big reasons why some people don't like Evernote for GTD.
Only you can decide whether Evernote's benefits outweigh the disadvantages. If you want to try Evernote for GTD, the David Allen Company setup guides would be a good place to start. Assuming you decide to stick with Evernote, you'll likely make tweaks and develop a system that's uniquely yours (although mine still largely resembles what's in the setup guide -- I like to keep things simple). If you end up not liking Evernote, nothing's stopping you from switching. It's not like a marriage. If you decide to leave your tool, you won't have to consult any lawyers. And to paraphrase Thomas Edison, your time won't have been wasted because you'll have ruled out Evernote as one thing that didn't work for you.