Well basically I will answer my question but hope more people will test those two and comment.
Imo Sngine is much better. More stable, a little bit faster (testing on my own dedicated webserver), better page speed test marks, much better in design and simplicity (users can easily find everything as Sngine is a lot like FB and it should be) and most important, Sngine is less buggy.
Everything works as it should in Sngine. Menu is great. Pages as well. Some small things like wallet, users can easily find it for example etc. Functions like points and pro subscription are explained well. Advertising, creating ads, ads stats etc. Translation is much better using "get text" with po/mo files if you compare to Wowonder where everything is translated inside system and written in database.
Now to be honest Wowonder has more functions because it is longer on the market and Sngine author is following Wo path (meaning he is creating pretty much a copy of Wo and its functions but more with FB look). Few examples are in Wo you can setup job offers and fundings and in Sngine you don't have those options yet, but that is not so important if you are starting your project.
Wo has actual Android/Ios apps. Sngine has only web-view apps. I don't see a problem there as well. Because those apps for Wo are from other authors and they are buggy too. I didn't try any app/web-app (I have 32 bit cpu at the moment so can't compile for example Android apps) but read a lot of comments. So many problems and bugs.
What I like most in Wo if compare to Sng is Wo has "follow" system (you can change to friends system if you like) where Sng has only "friends" system with following as addition.
It is a little bit simpler to use follow system where users just need to click to follow somebody without asking his permission. With friends system it is exactly like FB. Although they still can follow somebody in Sngine.
What do you think? Somebody else tested those two?