Magento 2 has been out for just about 1 year (https://magento.com/blog/magento-news/new-era-commerce-innovation) and we've been proactively testing, using and building sites on it ever since the developer release.
One con is there are not a ton of plugins yet. Being that its been 8 years in between Magento 1 and Magento 2 - this could take some time. The basics are there, but many companies that make plugins are still working through their own internal upgrades as Magento 2 is a completely new system.
That's really the only down side... here's some other differences and pros of this new version.
Full page caching (proactive, materialization) built in Magento 2.0 Community.
I’ve talked about this quite a bit in the past, but what this means is that instead of your Web server having to do a tremendous amount of slow database queries to render a page, this system builds out all of your pages in a static file system, so that page load times are 1-2 seconds (vs. 5-10 for non-cached pages). This is a huge deal.
Streamlined Checkout Process.
Nearly 80% of current Magento eCommerce sites have modified their checkout process to better streamline the process. With the Magento 2.0 checkout, guest checkout is assumed, and if you’re an existing customer, you can still log out without having to remember your password.
Pesky things like having to choose credit card type have been removed. (It’s easy for a computer to figure out your credit card type based on the first digit: 3 = Amex, 4 = Visa, 5 = MasterCard, etc.)
A clean, modern code base. Magento 2.0 is a fresh start.
Merchants who want to go with Magento 2.0 will know that legacy extensions or old, bad code will be removed. There’s no easy way to leave non-optimized code in place for Magento 2.0 sites.
Better performance / reduced table locking.
With larger scale Magento sites, we’ve seen performance issues with table locking when too many people are trying to place orders on a site.
For example, if you have 120 people trying to check out per minute, and you have queries that take 1 second to execute (and need to lock a table to write), then your system will crash.
For example, before an order is saved in Magento 1.9, the system saves key information to a Sales Grid Flat Table, so that a Magento admin user is able to see the new order in the Magento admin. But in order to do this, it has to lock the table, and this can back up processes to where people have 45 second or more page load times.
We’ve gotten around this specific issue with crazy levels of caching and very esoteric mySQL table optimization. But Magento 2.0 Community / Magento 2.0 Enterprise promises to have reduced this issue considerably.
Again, it's been 8 years in the making. So, the transition to Magento will take some time, it's still fairly new. However - it just might be the perfect time to take advantage of this new system!