If you add up all the services you get, the premium membership is a steal. For example, you’ll notice they include unlimited keyword research with a membership. Other paid keyword research tools sell for $49 or more just by themselves. Add in website hosting, and there’s another $10 / mo. Add on the website security package, and there’s another $10 per month (I’ve paid as much as $29 / mo just for website security). Just based on those things alone, Wealthy Affiliate is a great deal with all of the resources and tools you need in one convenient place. Not to mention all of the training, tutorials, and support that is included with the membership.
Affiliate marketing can be broken down into different levels of involvement: unattached, related and involved. Unattached affiliate marketing is a basic pay-per-click affiliate marketing campaign that requires little to no involvement with the product you are promoting. Related affiliate marketing requires you to have some authority and content on the product you are marketing, but you don't personally use the product. Involved affiliate marketing is perhaps the most effective, as you'll be marketing an affiliate product that you actually use and enjoy.
In the long-term, it affects your versatility, functionality, and, of course, your brand. In the short term, it can certainly add/take away a lot of headaches. That said, just like choosing a physical house or office, there is no such thing as an absolute “best” or “top” choice. There’s only the right choice relative to your goals, experience, and circumstances.