So here are some thoughts in regards to your 4 bullet points:

“1. Simple and more user friendly.”
We have a full time user experience design team that’s dedicated to keeping our product simple, focused, and user friendly. If our product isn’t simple to use or user friendly, we have failed you and your users. However, I don’t think we have… in fact, I believe our product is more simple and user friendly than the other alternatives out there. Our team actively researches our product and we use the data to help drive the design, performance, and innovation. Just recently, we launched a smarter menu—it optimizes itself for each one of your users. Visit http://www.addthis.com/features to learn more. This ensures that the right service is presented to the right user. We’ve seen dramatic lifts in traffic for all our publishers since more people are sharing. This is a win win for everyone. Publishers get more traffic. People can share with one click. And we look at all the data to make the product better for you. This is a core feature that makes AddThis more simple and friendly to use. And this is just the beginning—we want to get more feedback on how we can make our site, product, and overall experience better for you and your users.

“2. I love the ability to tell your myspace.com contact” and “3. Ability to tell all you facebook.com contact directly”
Actually, ShareThis no longer supports importing your facebook and myspace contacts. I actually really liked that feature as well in their menu—I agree, it was a good idea. We, too, wanted to add a similar feature to AddThis, but there was a problem—we would have broken our terms of service with Facebook. Just because you can, doesn’t mean we’re allowed to. Facebook is our friend too, so we have to abide by their rules. We came up with a really good alternative solution for now—instead, AddThis always takes you to their destination so you can manage your contacts there. For example, if you share with Facebook or MySpace, we redirect you their site so that you can manage, share and use your contacts. This is a better solution because there’s no middle man.

I, however, agree that there could be a easier way to integrate our contacts (other than email address books) into the sharing experience. We’re actually designing and testing some new features. Really-really cool features.

“4. Listed only the best Social Bookmarking website”
AddThis has over 170 services (and it’s growing, thanks to our open directory). No other sharing tool has this many services. These are services that have been recommended and submitted by the public. Submit your own (http://www.addthis.com/services/submit).

So what does this all mean? Well, when you combine the largest growing service directory with a smart menu that optimizes itself for each person, your website is going to be distributed more. For example, if someone doesn’t use MySpace, they’re probably not going to use it… so why keep it at the top of the list? Instead, they may use viadeo (french version of linked in), or meanéme (spanish bookmarking), or baidu (chinese bookmarking). AddThis supports all these services and more, and ensures that we maximize your distribution and reach around the world. Learn more about our service directory at http://www.addthis.com/services

Hopefully this helps. Again, let us know how we can help make AddThis better for you. You are one of the greatest sources of feedback we have. Please feel free to make suggestions on our forum (http://www.addthis.com/forum) or email our community manager, Justin. He responded to your post as well.