Sometime these would be interchangeable - other times not. It is going to depend on context. I like my tea without sugar. I like my tea with no sugar - this is a little odd - we tend not to say i like something, followed by a negative. But if someone was making tea and picked up the sugar bowl, you might say 'no sugar for me thanks'. Stress-free is probably more common usage than no stress, and whether you are talking about physical or mental stress might make a difference too. Without context it is hard to say much more. Hope that helps a bit.

Usually 'no' is more emphatic than 'without', but in a specific way. 'This cake is made without sugar'. - Saying 'without' means that something *shouldn't* be there. 'This cake is made with no sugar'. - This stresses the *positive* absence of something, i.e. the lack of sugar in the lack is implied to be a good thing. That said, 'without' is the more common structure, so when in doubt, say 'without'. I apologise for the inadvertent rhyme. That said, there are certain turns of phrase where 'without' is stronger. 'Without doubt' is used to express absolute certainty about an opinion, and 'no doubt' is just being very certain about an opinon.