Drupal 7 is a powerful, robust tool, that allows your site to grow in almost any way imaginable. But with this flexibility comes a steep learning curve. Drupal 7 has a reputation for being hard to use, harder to learn, slow, and only easy to develop if you already know what you're doing.
Drupal 8 is going enterprize. It will probably be easier to use, but still harder to learn. It will also be slower to run than Drupal 7 (unless you have a beefy hosting environment). The code in D8 is very different from D7. Developers for D8 are going to be more expensive, harder to find, and development time is going to be longer (at least initially) as everyone learns the new systems.
Small to medium-sized businesses are already feeling the increasing development (and hosting) costs that are associated with running Drupal websites. How much of the Drupal ecosystem is made up of these sites, people, and developers? How will they fare in a Drupal 8 world? How does that affect the entire Drupal ecosystem?
I'd like to offer an alternative: Backdrop CMS.
Backdrop CMS is a fork of Drupal. It splits from Drupal 8 very early in the development cycle, but excludes many modules and features that are unnecessary for the majority of us. It's code is similar to that of Drupal 7 but also includes some important new features comparable to similar ones in Drupal 8.
The primary goal of the Backdrop project is to decrease the barrier to entry. This includes lower costs, lower system requirements (meaning more affordable hosting), simpler user interfaces, and code that is easier for anyone to learn.
Come see where Backdrop CMS is today, what is in store for the 1.1.0 release, and help us imagine our future.