This is coming from an AMD user. If you have the 4770 I would hold out a few months. Maybe grab a little extra ram if you want. I think I paid 13 for 4gb ddr3 1600 on eBay recently for some ram for an old i7 3770 Dell optiplex system I'm setting up for my wife's home office.
That said, AMD ryzen is great. Single core performance I think is around haswell, which is of course what you have now. However, the word on the street is that supposedly zen 2 is coming about June/July. No hard facts yet, but this will be their redesign of ryzen and the move to 7nm. They are talking mainstream CPUs of 16 cores 32 threads I think for the high end, not counting threadripper, and possibly speeds of around 5ghz. Plus they seem to think single core performance will improve.
Again, no hard facts, but apparently at CES they had an engineering sample 8 core/16 thread CPU running and supposedly beating out an i9 CPU from Intel. So lot of rumors. I personally have three 1st generation 1700x myself and am happy with it. In your case, I would hold out for zen 2 for a truly meaningful upgrade if I were in your shoes I think.
As far as comparison with the ryzen 2600 however, it will be close to your CPU in single thread applications and games that are single thread. But it would do slightly better in multithreaded apps and games being 6 cores 12 threads.