I tried a few mods during 0.16 but just for two days. I prefer playing without mods, some of them look really cool and are really helpfull such as mechjeb, but achieving perfect orbits, randezvous, landings and completing missions successfully with stock rockets or spaceplanes is so satistying and fun ! And it is also much more challenging. Of course everyone is free to play the way they want . I advice new players or players that have never tried mods to try them at least once... they may improve your gameplay.